X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=python%2Fcumulus%2Fstore%2F__init__.py;h=a59c21741072df0a9c47f3d500d845410b00ca0c;hb=fae5b159f9526d9903121fea3d5da7ba4b4ba73b;hp=0899d70b04c9a03e1b0e1e32bc2166eca4ae4e88;hpb=c343597dac79f9edc63d95d881625a317fadb1d9;p=cumulus.git

diff --git a/python/cumulus/store/__init__.py b/python/cumulus/store/__init__.py
index 0899d70..a59c217 100644
--- a/python/cumulus/store/__init__.py
+++ b/python/cumulus/store/__init__.py
@@ -16,7 +16,18 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-import exceptions, re, urlparse
+from __future__ import division, print_function, unicode_literals
+
+import importlib
+import re
+try:
+    # Python 3
+    from urllib import parse as urlparse
+    from urllib.parse import quote, unquote
+except ImportError:
+    # Python 2
+    from urllib import quote, unquote
+    import urlparse
 
 type_patterns = {
     'checksums': re.compile(r"^snapshot-(.*)\.(\w+)sums$"),
@@ -24,36 +35,24 @@ type_patterns = {
     'snapshots': re.compile(r"^snapshot-(.*)\.(cumulus|lbs)$")
 }
 
-class NotFoundError(exceptions.KeyError):
+class NotFoundError(KeyError):
     """Exception thrown when a file is not found in a repository."""
 
     pass
 
-class Store (object):
+class Store(object):
     """Base class for all cumulus storage backends."""
 
-    def __new__ (cls, url, **kw):
-        """ Return the correct sub-class depending on url,
-        pass parsed url parameters to object
+    def __init__(self, url):
+        """Initializes a new storage backend.
+
+        Params:
+          url: The parsed (by urlsplit) URL that specifies the storage
+              location.
         """
-        if cls != Store:
-            return super(Store, cls).__new__(cls, url, **kw)
-        (scheme, netloc, path, params, query, fragment) \
-            = urlparse.urlparse(url)
-
-        try:
-            cumulus = __import__('cumulus.store.%s' % scheme, globals())
-            subcls = getattr (cumulus.store, scheme).Store
-            obj = super(Store, cls).__new__(subcls, url, **kw)
-            obj.scheme = scheme
-            obj.netloc = netloc
-            obj.path = path
-            obj.params = params
-            obj.query = query
-            obj.fragment = fragment
-            return obj
-        except ImportError:
-            raise NotImplementedError, "Scheme %s not implemented" % scheme
+        pass
+
+    # TODO: Implement context manager.
 
     def list(self, path):
         raise NotImplementedError
@@ -70,7 +69,7 @@ class Store (object):
     def stat(self, path):
         raise NotImplementedError
 
-    def scan(self):
+    def scan(self, path):
         """Cache file information stored in this backend.
 
         This might make subsequent list or stat calls more efficient, but this
@@ -89,4 +88,23 @@ class Store (object):
         self.close()
 
 def open(url):
-    return Store(url)
+    """Parse a storage url, then locate and initialize a backend for it."""
+    parsed_url = urlparse.urlsplit(url)
+
+    # If there is no scheme, fall back to treating the string as local path and
+    # construct a file:/// URL.
+    if not parsed_url.scheme:
+        parsed_url = urlparse.SplitResult("file", "", quote(url), "", "")
+
+    try:
+        # TODO: Support a registry for schemes that don't map to a module.
+        if re.match(r"^\w+$", parsed_url.scheme):
+            handler = importlib.import_module("cumulus.store.%s" %
+                                              parsed_url.scheme)
+            obj = handler.Store(parsed_url)
+            return obj
+    except ImportError:
+        # Fall through to error below
+        pass
+
+    raise NotImplementedError("Scheme %s not implemented" % scheme)