--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/buttercup/source.py	Mon May 30 13:40:13 2011 -0700
@@ -0,0 +1,37 @@
+import os
+import subprocess
+
+class Source(object):
+    """abstract base class for VCS source"""
+    def __init__(self, uri, srcdir=None):
+        self.uri = uri
+        self.srcdir = srcdir or os.getcwd()
+
+    @classmethod
+    def directory_name(cls, uri):
+        """return relative directory name from self.uri"""
+        return uri.rstrip('/').split('/')[-1]
+
+    def directory(self):
+        return os.path.join(self.srcdir, self.directory_name(self.uri))
+
+class HgSource(Source):
+    """mercurial source"""
+
+    def update(self):
+        """updates a checkout or does one if it does not exist"""
+
+class GitSource(Source):
+
+    @classmethod
+    def directory_name(cls, uri):
+        ext = '.git'
+        if uri.endswith(uri):
+            uri = uri[:-len(ext)]
+        return Source.directory_name(uri)
+
+if __name__ == '__main__':
+    source = HgSource('http://k0s.org/hg/pyloader')
+    print source.directory()
+    source = GitSource('git://github.com/mozilla/toolbox.git')
+    print source.directory()