A Patcher class

tests/test_formatting.py

@@ -4,7 +4,7 @@
 import unittest
 
 from lxml import etree
-from xmldiff import diff, formatting, main, actions
+from xmldiff import formatting, main, actions
 
 from .testing import generate_filebased_cases
 
@@ -298,7 +298,7 @@ def test_update_text_in(self):
 
         left = u'<document><node>This is a bit of text, right' + END
         action = actions.UpdateTextIn('/document/node',
-                                   'Also a bit of text, rick')
+                                      'Also a bit of text, rick')
         expected = START + u'><diff:delete>This is</diff:delete><diff:insert>'\
             u'Also</diff:insert> a bit of text, ri<diff:delete>ght'\
             u'</diff:delete><diff:insert>ck</diff:insert>' + END
@@ -316,7 +316,7 @@ def test_update_text_after_1(self):
     def test_update_text_after_2(self):
         left = u'<document><node/>This is a bit of text, right</document>'
         action = actions.UpdateTextAfter('/document/node',
-                                      'Also a bit of text, rick')
+                                         'Also a bit of text, rick')
         expected = START + u'/><diff:delete>This is</diff:delete>'\
             u'<diff:insert>Also</diff:insert> a bit of text, ri<diff:delete>'\
             u'ght</diff:delete><diff:insert>ck</diff:insert></document>'
@@ -396,7 +396,7 @@ def test_update_text_in(self):
         self._format_test(action, expected)
 
         action = actions.UpdateTextIn('/document/node',
-                                   'Also a bit of text, "rick"')
+                                      'Also a bit of text, "rick"')
         expected = '[update-text, /document/node, '\
             u'"Also a bit of text, \\"rick\\""]'
         self._format_test(action, expected)
@@ -408,7 +408,7 @@ def test_update_text_after_1(self):
 
     def test_update_text_after_2(self):
         action = actions.UpdateTextAfter('/document/node',
-                                      'Also a bit of text, rick')
+                                         'Also a bit of text, rick')
         expected = '[update-text-after, /document/node, '\
             u'"Also a bit of text, rick"]'
         self._format_test(action, expected)
@@ -476,7 +476,7 @@ def test_update_text_in(self):
         self._format_test(action, expected)
 
         action = actions.UpdateTextIn('/document/node',
-                                   'Also a bit of text, "rick"')
+                                      'Also a bit of text, "rick"')
         expected = '[update, /document/node/text()[1], '\
             u'"Also a bit of text, \\"rick\\""]'
         self._format_test(action, expected)
@@ -488,7 +488,7 @@ def test_update_text_after_1(self):
 
     def test_update_text_after_2(self):
         action = actions.UpdateTextAfter('/document/node',
-                                      'Also a bit of text, rick')
+                                         'Also a bit of text, rick')
         expected = '[update, /document/node/text()[2], '\
             u'"Also a bit of text, rick"]'
         self._format_test(action, expected)

xmldiff/diff.py

@@ -384,8 +384,8 @@ def diff(self, left=None, right=None):
                 pos = self.find_pos(rnode)
                 # (ii)
                 if rnode.tag is etree.Comment:
-                    yield actions.InsertComment(utils.getpath(ltarget, ltree), pos,
-                                        rnode.text)
+                    yield actions.InsertComment(
+                        utils.getpath(ltarget, ltree), pos, rnode.text)
                     lnode = etree.Comment(rnode.text)
                 else:
                     yield actions.InsertNode(utils.getpath(ltarget, ltree),

xmldiff/patch.py

@@ -0,0 +1,59 @@
+from lxml import etree
+
+
+class Patcher(object):
+
+    def handle_action(self, action, tree):
+        action_type = type(action)
+        method = getattr(self, '_handle_' + action_type.__name__)
+        method(action, tree)
+
+    def _handle_DeleteNode(self, action, tree):
+        node = tree.xpath(action.node)[0]
+        node.getparent().remove(node)
+
+    def _handle_InsertNode(self, action, tree):
+        target = tree.xpath(action.target)[0]
+        node = target.makeelement(action.tag)
+        target.insert(action.position, node)
+
+    def _handle_RenameNode(self, action, tree):
+        tree.xpath(action.node)[0].tag = action.tag
+
+    def _handle_MoveNode(self, action, tree):
+        node = tree.xpath(action.node)[0]
+        node.getparent().remove(node)
+        target = tree.xpath(action.target)[0]
+        target.insert(action.position, node)
+
+    def _handle_UpdateTextIn(self, action, tree):
+        tree.xpath(action.node)[0].text = action.text
+
+    def _handle_UpdateTextAfter(self, action, tree):
+        tree.xpath(action.node)[0].tail = action.text
+
+    def _handle_UpdateAttrib(self, action, tree):
+        node = tree.xpath(action.node)[0]
+        # This should not be used to insert new attributes.
+        assert action.name in node.attrib
+        node.attrib[action.name] = action.value
+
+    def _handle_DeleteAttrib(self, action, tree):
+        del tree.xpath(action.node)[0].attrib[action.name]
+
+    def _handle_InsertAttrib(self, action, tree):
+        node = tree.xpath(action.node)[0]
+        # This should not be used to update existing attributes.
+        assert action.name not in node.attrib
+        node.attrib[action.name] = action.value
+
+    def _handle_RenameAttrib(self, action, tree):
+        node = tree.xpath(action.node)[0]
+        assert action.oldname in node.attrib
+        assert action.newname not in node.attrib
+        node.attrib[action.newname] = node.attrib[action.oldname]
+        del node.attrib[action.oldname]
+
+    def _handle_InsertComment(self, action, tree):
+        target = tree.xpath(action.target)[0]
+        target.insert(action.position, etree.Comment(action.text))