[modules] Add new module to display git information

This module uses xcwd to retrieve the directory of the currently focused
window and, if any of the parent directories is a git repository,
displays basic information about the repository.

Right now, only the current branch name is displayed.

bumblebee/modules/git.py

@@ -0,0 +1,50 @@
+# pylint: disable=C0111,R0903
+
+"""Print the branch and git status for the
+currently focused window.
+
+Requires:
+    * xcwd
+    * Python module 'pygit2'
+"""
+
+import os
+import string
+import pygit2
+
+import bumblebee.input
+import bumblebee.output
+import bumblebee.engine
+import bumblebee.util
+
+class Module(bumblebee.engine.Module):
+    def __init__(self, engine, config):
+        super(Module, self).__init__(engine, config,
+            bumblebee.output.Widget(full_text=self.gitinfo)
+        )
+        self._fmt = self.parameter("format", "{branch}")
+
+    def gitinfo(self, widget):
+        info = ""
+        directory = None
+        data = {
+            "branch": "n/a",
+        }
+        try:
+            directory = bumblebee.util.execute("xcwd").strip()
+            directory = self._get_git_root(directory)
+            repo = pygit2.Repository(directory)
+            data["branch"] = repo.head.shorthand
+        except Exception as e:
+            return e
+
+        return string.Formatter().vformat(self._fmt, (), data)
+
+    def _get_git_root(self, directory):
+        while directory != "/":
+            if os.path.exists(os.path.join(directory, ".git")):
+                return directory
+            directory = "/".join(directory.split("/")[0:-1])
+        return None
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4