2760: Assign a generic name if link_class=name and no name is given.

[arvados.git] / services / api / app / models / link.rb

diff --git a/services/api/app/models/link.rb b/services/api/app/models/link.rb
index 37b4c899f9fdaa97e9c41b7f92ace611befd833f..9f4f51016c5d5f2337843309522873e537975202 100644 (file)
--- a/services/api/app/models/link.rb
+++ b/services/api/app/models/link.rb
@@ -1,10 +1,11 @@
 class Link < ArvadosModel
-  include AssignUuid
+  include HasUuid
   include KindAndEtag
   include CommonApiTemplate
   serialize :properties, Hash
   before_create :permission_to_attach_to_objects
   before_update :permission_to_attach_to_objects
+  before_create :assign_generic_name_if_none_given
   after_update :maybe_invalidate_permissions_cache
   after_create :maybe_invalidate_permissions_cache
   after_destroy :maybe_invalidate_permissions_cache
@@ -40,6 +41,48 @@ class Link < ArvadosModel
 
   protected
 
+  def assign_generic_name_if_none_given
+    if new_record? and link_class == 'name' and (!name or name.empty?)
+      # Creating a name link with no name means "invent a generic
+      # name, like New Foo (1)"
+
+      head_class = ArvadosModel::resource_class_for_uuid(head_uuid)
+      if !head_class
+        errors.add :name, 'cannot be automatically assigned for this uuid'
+        return
+      end
+      name_base = "New " + head_class.to_s.underscore.humanize.downcase
+      if not Link.where(link_class: link_class,
+                        tail_uuid: tail_uuid,
+                        name: name_base).any?
+        self.name = name_base
+      else
+        # Find how many digits the largest N has among "New model (N)" names
+        maxlen = ActiveRecord::Base.connection.
+          execute("SELECT max(length(name)) maxlen FROM links "\
+                  "WHERE link_class='name' "\
+                  "AND tail_uuid=#{Link.sanitize(tail_uuid)} "\
+                  "AND name~#{Link.sanitize "#{name_base} \\([0-9]+\\)"}")[0]
+        if maxlen and maxlen['maxlen']
+          # Find the largest N by sorting alphanumerically
+          maxname = ActiveRecord::Base.connection.
+            execute("SELECT max(name) maxname FROM links "\
+                    "WHERE link_class='name' "\
+                    "AND tail_uuid=#{Link.sanitize(tail_uuid)} "\
+                    "AND length(name)=#{maxlen['maxlen']} "\
+                    "AND name~#{Link.sanitize "#{name_base} \\([0-9]+\\)"}"
+                    )[0]['maxname']
+          n = maxname.match(/\(([0-9]+)\)$/)[1].to_i
+          n += 1
+        else
+          # "New foo" is taken, but "New foo (1)" isn't.
+          n = 1
+        end
+        self.name = name_base + " (#{n})"
+      end
+    end
+  end
+
   def permission_to_attach_to_objects
     # Anonymous users cannot write links
     return false if !current_user
@@ -52,7 +95,7 @@ class Link < ArvadosModel
 
     # All users can grant permissions on objects they own
     head_obj = self.class.
-      kind_class(self.head_uuid).
+      resource_class_for_uuid(self.head_uuid).
       where('uuid=?',head_uuid).
       first
     if head_obj
@@ -85,8 +128,13 @@ class Link < ArvadosModel
 
   def name_link_has_valid_name
     if link_class == 'name'
-      unless name.is_a? String and !name.empty?
-        errors.add('name', 'must be a non-empty string')
+      if new_record? and (!name or name.empty?)
+        # Unique name will be assigned in before_create filter
+        true
+      else
+        unless name.is_a? String and !name.empty?
+          errors.add('name', 'must be a non-empty string')
+        end
       end
     else
       true