Example of refactoring using rope library.

tools/telemetry/third_party/rope/rope/refactor/method_object.py

Index: tools/telemetry/third_party/rope/rope/refactor/method_object.py
diff --git a/tools/telemetry/third_party/rope/rope/refactor/method_object.py b/tools/telemetry/third_party/rope/rope/refactor/method_object.py
new file mode 100644
index 0000000000000000000000000000000000000000..29ce429db6115a389cda2b8adf6b7e0d194324f0
--- /dev/null
+++ b/tools/telemetry/third_party/rope/rope/refactor/method_object.py
@@ -0,0 +1,90 @@
+import warnings
+
+from rope.base import libutils
+from rope.base import pyobjects, exceptions, change, evaluate, codeanalyze
+from rope.refactor import sourceutils, occurrences, rename
+
+
+class MethodObject(object):
+
+    def __init__(self, project, resource, offset):
+        self.project = project
+        this_pymodule = self.project.get_pymodule(resource)
+        pyname = evaluate.eval_location(this_pymodule, offset)
+        if pyname is None or not isinstance(pyname.get_object(),
+                                            pyobjects.PyFunction):
+            raise exceptions.RefactoringError(
+                'Replace method with method object refactoring should be '
+                'performed on a function.')
+        self.pyfunction = pyname.get_object()
+        self.pymodule = self.pyfunction.get_module()
+        self.resource = self.pymodule.get_resource()
+
+    def get_new_class(self, name):
+        body = sourceutils.fix_indentation(
+            self._get_body(), sourceutils.get_indent(self.project) * 2)
+        return 'class %s(object):\n\n%s%sdef __call__(self):\n%s' % \
+               (name, self._get_init(),
+                ' ' * sourceutils.get_indent(self.project), body)
+
+    def get_changes(self, classname=None, new_class_name=None):
+        if new_class_name is not None:
+            warnings.warn(
+                'new_class_name parameter is deprecated; use classname',
+                DeprecationWarning, stacklevel=2)
+            classname = new_class_name
+        collector = codeanalyze.ChangeCollector(self.pymodule.source_code)
+        start, end = sourceutils.get_body_region(self.pyfunction)
+        indents = sourceutils.get_indents(
+            self.pymodule.lines, self.pyfunction.get_scope().get_start()) + \
+            sourceutils.get_indent(self.project)
+        new_contents = ' ' * indents + 'return %s(%s)()\n' % \
+                       (classname, ', '.join(self._get_parameter_names()))
+        collector.add_change(start, end, new_contents)
+        insertion = self._get_class_insertion_point()
+        collector.add_change(insertion, insertion,
+                             '\n\n' + self.get_new_class(classname))
+        changes = change.ChangeSet(
+            'Replace method with method object refactoring')
+        changes.add_change(change.ChangeContents(self.resource,
+                                                 collector.get_changed()))
+        return changes
+
+    def _get_class_insertion_point(self):
+        current = self.pyfunction
+        while current.parent != self.pymodule:
+            current = current.parent
+        end = self.pymodule.lines.get_line_end(current.get_scope().get_end())
+        return min(end + 1, len(self.pymodule.source_code))
+
+    def _get_body(self):
+        body = sourceutils.get_body(self.pyfunction)
+        for param in self._get_parameter_names():
+            body = param + ' = None\n' + body
+            pymod = libutils.get_string_module(
+                self.project, body, self.resource)
+            pyname = pymod[param]
+            finder = occurrences.create_finder(self.project, param, pyname)
+            result = rename.rename_in_module(finder, 'self.' + param,
+                                             pymodule=pymod)
+            body = result[result.index('\n') + 1:]
+        return body
+
+    def _get_init(self):
+        params = self._get_parameter_names()
+        indents = ' ' * sourceutils.get_indent(self.project)
+        if not params:
+            return ''
+        header = indents + 'def __init__(self'
+        body = ''
+        for arg in params:
+            new_name = arg
+            if arg == 'self':
+                new_name = 'host'
+            header += ', %s' % new_name
+            body += indents * 2 + 'self.%s = %s\n' % (arg, new_name)
+        header += '):'
+        return '%s\n%s\n' % (header, body)
+
+    def _get_parameter_names(self):
+        return self.pyfunction.get_param_names()