ENH: add a linkcode extension

1 files changed, 72 insertions, 0 deletions

diff --git a/sphinx/ext/linkcode.py b/sphinx/ext/linkcode.py
new file mode 100644
index 000000000..ffe5b9c09
--- /dev/null
+++ b/sphinx/ext/linkcode.py
@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+"""
+    sphinx.ext.linkcode
+    ~~~~~~~~~~~~~~~~~~~
+
+    Add external links to module code in Python object descriptions.
+
+    :copyright: Copyright 2007-2011 by the Sphinx team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+from docutils import nodes
+
+from sphinx import addnodes
+from sphinx.locale import _
+from sphinx.errors import SphinxError
+
+class LinkcodeError(SphinxError):
+    category = "linkcode error"
+
+def doctree_read(app, doctree):
+    env = app.builder.env
+
+    resolve_target = getattr(env.config, 'linkcode_resolve', None)
+    if not callable(env.config.linkcode_resolve):
+        raise LinkcodeError(
+            "Function `linkcode_resolve` is not given in conf.py")
+
+    domain_keys = dict(
+        py=['module', 'fullname'],
+        c=['names'],
+        cpp=['names'],
+        js=['object', 'fullname'],
+    )
+
+    for objnode in doctree.traverse(addnodes.desc):
+        domain = objnode.get('domain')
+        uris = set()
+        for signode in objnode:
+            if not isinstance(signode, addnodes.desc_signature):
+                continue
+
+            # Convert signode to a specified format
+            info = {}
+            for key in domain_keys.get(domain, []):
+                value = signode.get(key)
+                if not value:
+                    value = ''
+                info[key] = value
+            if not info:
+                continue
+
+            # Call user code to resolve the link
+            uri = resolve_target(domain, info)
+            if not uri:
+                # no source
+                continue
+
+            if uri in uris or not uri:
+                # only one link per name, please
+                continue
+            uris.add(uri)
+
+            onlynode = addnodes.only(expr='html')
+            onlynode += nodes.reference('', '', internal=False, refuri=uri)
+            onlynode[0] += nodes.inline('', _('[source]'),
+                                        classes=['viewcode-link'])
+            signode += onlynode
+
+def setup(app):
+    app.connect('doctree-read', doctree_read)
+    app.add_config_value('linkcode_resolve', None, 'env')