1 files changed, 23 insertions, 3 deletions
diff --git a/sphinx/util/docutils.py b/sphinx/util/docutils.py
index 00ea5919e..bfaff758f 100644
--- a/sphinx/util/docutils.py
+++ b/sphinx/util/docutils.py
@@ -5,7 +5,7 @@
 
     Utility functions for docutils.
 
-    :copyright: Copyright 2007-2017 by the Sphinx team, see AUTHORS.
+    :copyright: Copyright 2007-2018 by the Sphinx team, see AUTHORS.
     :license: BSD, see LICENSE for details.
 """
 from __future__ import absolute_import
@@ -18,7 +18,7 @@ from contextlib import contextmanager
 
 import docutils
 from docutils.languages import get_language
-from docutils.statemachine import ViewList
+from docutils.statemachine import StateMachine, ViewList
 from docutils.parsers.rst import directives, roles, convert_directive_function
 from docutils.utils import Reporter
 
@@ -31,8 +31,9 @@ report_re = re.compile('^(.+?:(?:\\d+)?): \\((DEBUG|INFO|WARNING|ERROR|SEVERE)/(
 
 if False:
     # For type annotation
-    from typing import Any, Callable, Iterator, List, Tuple  # NOQA
+    from typing import Any, Callable, Generator, Iterator, List, Tuple  # NOQA
     from docutils import nodes  # NOQA
+    from docutils.statemachine import State  # NOQA
     from sphinx.environment import BuildEnvironment  # NOQA
     from sphinx.io import SphinxFileInput  # NOQA
 
@@ -216,3 +217,22 @@ def directive_helper(obj, has_content=None, argument_spec=None, **option_spec):
             raise ExtensionError(__('when adding directive classes, no '
                                     'additional arguments may be given'))
         return obj
+
+
+@contextmanager
+def switch_source_input(state, content):
+    # type: (State, ViewList) -> Generator
+    """Switch current source input of state temporarily."""
+    try:
+        # remember the original ``get_source_and_line()`` method
+        get_source_and_line = state.memo.reporter.get_source_and_line
+
+        # replace it by new one
+        state_machine = StateMachine([], None)
+        state_machine.input_lines = content
+        state.memo.reporter.get_source_and_line = state_machine.get_source_and_line
+
+        yield
+    finally:
+        # restore the method
+        state.memo.reporter.get_source_and_line = get_source_and_line