Add nested groups support on data leveldz-nested-groups

* add parent_id field to namespaces table to store relation with nested groups
* create routes table to keep information about full path of every group and project
* project/group lookup by full path from routes table

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/app/models/concerns/routable.rb b/app/models/concerns/routable.rb
new file mode 100644
index 00000000000..d36bb9da296
--- /dev/null
+++ b/app/models/concerns/routable.rb
@@ -0,0 +1,70 @@
+# Store object full path in separate table for easy lookup and uniq validation
+# Object must have path db field and respond to full_path and full_path_changed? methods.
+module Routable
+  extend ActiveSupport::Concern
+
+  included do
+    has_one :route, as: :source, autosave: true, dependent: :destroy
+
+    validates_associated :route
+
+    before_validation :update_route_path, if: :full_path_changed?
+  end
+
+  class_methods do
+    # Finds a single object by full path match in routes table.
+    #
+    # Usage:
+    #
+    #     Klass.find_by_full_path('gitlab-org/gitlab-ce')
+    #
+    # Returns a single object, or nil.
+    def find_by_full_path(path)
+      # On MySQL we want to ensure the ORDER BY uses a case-sensitive match so
+      # any literal matches come first, for this we have to use "BINARY".
+      # Without this there's still no guarantee in what order MySQL will return
+      # rows.
+      binary = Gitlab::Database.mysql? ? 'BINARY' : ''
+
+      order_sql = "(CASE WHEN #{binary} routes.path = #{connection.quote(path)} THEN 0 ELSE 1 END)"
+
+      where_paths_in([path]).reorder(order_sql).take
+    end
+
+    # Builds a relation to find multiple objects by their full paths.
+    #
+    # Usage:
+    #
+    #     Klass.where_paths_in(%w{gitlab-org/gitlab-ce gitlab-org/gitlab-ee})
+    #
+    # Returns an ActiveRecord::Relation.
+    def where_paths_in(paths)
+      wheres = []
+      cast_lower = Gitlab::Database.postgresql?
+
+      paths.each do |path|
+        path = connection.quote(path)
+        where = "(routes.path = #{path})"
+
+        if cast_lower
+          where = "(#{where} OR (LOWER(routes.path) = LOWER(#{path})))"
+        end
+
+        wheres << where
+      end
+
+      if wheres.empty?
+        none
+      else
+        joins(:route).where(wheres.join(' OR '))
+      end
+    end
+  end
+
+  private
+
+  def update_route_path
+    route || build_route(source: self)
+    route.path = full_path
+  end
+end