Optimize bucket listing

When Container Hierarchy is used, a lot of containers
may be created. This patch will use first character of
encoded delimiter of Container Hierarchy as delimiter.

Since S3 doesn't support delimiter in bucket listing (and
results are not compliant with bucket name for old SDS),
we also skip `subdir` entries when generating results.

oioswift/proxy/controllers/account.py

@@ -39,6 +39,8 @@
 
 from oioswift.utils import handle_oio_timeout, handle_service_busy, \
     REQID_HEADER
+from oioswift.common.middleware.container_hierarchy \
+        import ContainerHierarchyMiddleware as CH
 
 
 def get_response_headers(info):
@@ -57,7 +59,7 @@ def get_response_headers(info):
 
 
 def account_listing_response(account, req, response_content_type,
-                             info=None, listing=None):
+                             info=None, listing=None, s3_buckets_only=False):
     now = time.time()
     if info is None:
         info = {'containers': 0,
@@ -77,7 +79,8 @@ def account_listing_response(account, req, response_content_type,
         data = []
         for (name, object_count, bytes_used, is_subdir, mtime) in listing:
             if is_subdir:
-                data.append({'subdir': name})
+                if not s3_buckets_only:
+                    data.append({'subdir': name})
             else:
                 data.append({'name': name, 'count': object_count,
                              'bytes': bytes_used,
@@ -88,8 +91,9 @@ def account_listing_response(account, req, response_content_type,
                        '<account name=%s>' % saxutils.quoteattr(account)]
         for (name, object_count, bytes_used, is_subdir, mtime) in listing:
             if is_subdir:
-                output_list.append(
-                    '<subdir name=%s />' % saxutils.quoteattr(name))
+                if not s3_buckets_only:
+                    output_list.append(
+                        '<subdir name=%s />' % saxutils.quoteattr(name))
             else:
                 item = '<container><name>%s</name><count>%s</count>' \
                        '<bytes>%s</bytes><last_modified>%s</last_modified>' \
@@ -174,6 +178,7 @@ def get_account_listing_resp(self, req):
         s3_buckets_only = False
         if req.environ.get('swift.source') == 'S3':
             s3_buckets_only = True
+            delimiter = CH.ENCODED_DELIMITER[0]
 
         oio_headers = {REQID_HEADER: self.trans_id}
         info = None
@@ -195,7 +200,7 @@ def get_account_listing_resp(self, req):
                 delimiter=delimiter, headers=oio_headers)
         return account_listing_response(
             self.account_name, req, get_listing_content_type(req),
-            info=info, listing=listing)
+            info=info, listing=listing, s3_buckets_only=s3_buckets_only)
 
     @public
     @handle_account_not_found_autocreate