1 files changed, 106 insertions, 0 deletions
diff --git a/sphinx/transforms/post_transforms/code.py b/sphinx/transforms/post_transforms/code.py
new file mode 100644
index 000000000..f0c1d0097
--- /dev/null
+++ b/sphinx/transforms/post_transforms/code.py
@@ -0,0 +1,106 @@
+# -*- coding: utf-8 -*-
+"""
+    sphinx.transforms.post_transforms.code
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    transforms for code-blocks.
+
+    :copyright: Copyright 2007-2018 by the Sphinx team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+import sys
+from typing import NamedTuple
+
+from docutils import nodes
+from six import text_type
+
+from sphinx import addnodes
+from sphinx.transforms import SphinxTransform
+
+if False:
+    # For type annotation
+    from typing import Any, Dict, List  # NOQA
+    from sphinx.application import Sphinx  # NOQA
+
+
+HighlightSetting = NamedTuple('HighlightSetting', [('language', text_type),
+                                                   ('lineno_threshold', int)])
+
+
+class HighlightLanguageTransform(SphinxTransform):
+    """
+    Apply highlight_language to all literal_block nodes.
+
+    This refers both :confval:`highlight_language` setting and
+    :rst:dir:`highlightlang` directive.  After processing, this transform
+    removes ``highlightlang`` node from doctree.
+    """
+    default_priority = 400
+
+    def apply(self):
+        visitor = HighlightLanguageVisitor(self.document,
+                                           self.config.highlight_language)
+        self.document.walkabout(visitor)
+
+        for node in self.document.traverse(addnodes.highlightlang):
+            node.parent.remove(node)
+
+
+class HighlightLanguageVisitor(nodes.NodeVisitor):
+    def __init__(self, document, default_language):
+        # type: (nodes.document, unicode) -> None
+        self.default_setting = HighlightSetting(default_language, sys.maxsize)
+        self.settings = []  # type: List[HighlightSetting]
+        nodes.NodeVisitor.__init__(self, document)
+
+    def unknown_visit(self, node):
+        # type: (nodes.Node) -> None
+        pass
+
+    def unknown_departure(self, node):
+        # type: (nodes.Node) -> None
+        pass
+
+    def visit_document(self, node):
+        # type: (nodes.Node) -> None
+        self.settings.append(self.default_setting)
+
+    def depart_document(self, node):
+        # type: (nodes.Node) -> None
+        self.settings.pop()
+
+    def visit_start_of_file(self, node):
+        # type: (nodes.Node) -> None
+        self.settings.append(self.default_setting)
+
+    def depart_start_of_file(self, node):
+        # type: (nodes.Node) -> None
+        self.settings.pop()
+
+    def visit_highlightlang(self, node):
+        # type: (addnodes.highlightlang) -> None
+        self.settings[-1] = HighlightSetting(node['lang'], node['linenothreshold'])
+
+    def visit_literal_block(self, node):
+        # type: (nodes.literal_block) -> None
+        setting = self.settings[-1]
+        if 'language' not in node:
+            node['language'] = setting.language
+            node['force_highlighting'] = False
+        else:
+            node['force_highlighting'] = True
+        if 'linenos' not in node:
+            lines = node.astext().count('\n')
+            node['linenos'] = (lines >= setting.lineno_threshold - 1)
+
+
+def setup(app):
+    # type: (Sphinx) -> Dict[unicode, Any]
+    app.add_post_transform(HighlightLanguageTransform)
+
+    return {
+        'version': 'builtin',
+        'parallel_read_safe': True,
+        'parallel_write_safe': True,
+    }