X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/04bb94072486e32ed9784be3a22c43d961c84bee..9cfbcdf804974812b1a4ec514f5dc7902fce6137:/apps/workbench/app/models/collection.rb

diff --git a/apps/workbench/app/models/collection.rb b/apps/workbench/app/models/collection.rb
index 94a2b95916..5460e9a6e0 100644
--- a/apps/workbench/app/models/collection.rb
+++ b/apps/workbench/app/models/collection.rb
@@ -1,4 +1,12 @@
 class Collection < ArvadosBase
+
+  MD5_EMPTY = 'd41d8cd98f00b204e9800998ecf8427e'
+
+  # Return true if the given string is the locator of a zero-length blob
+  def self.is_empty_blob_locator? locator
+    !!locator.to_s.match("^#{MD5_EMPTY}(\\+.*)?\$")
+  end
+
   def total_bytes
     if files
       tot = 0
@@ -13,7 +21,16 @@ class Collection < ArvadosBase
     false
   end
 
+  def self.creatable?
+    false
+  end
+
   def provenance
     $arvados_api_client.api "collections/#{self.uuid}/", "provenance"
   end
+
+  def used_by
+    $arvados_api_client.api "collections/#{self.uuid}/", "used_by"
+  end
+
 end