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>

9 files changed, 134 insertions, 89 deletions

diff --git a/app/controllers/admin/groups_controller.rb b/app/controllers/admin/groups_controller.rb
index aa7570cd896..1e3d194e9f9 100644
--- a/app/controllers/admin/groups_controller.rb
+++ b/app/controllers/admin/groups_controller.rb
@@ -56,7 +56,7 @@ class Admin::GroupsController < Admin::ApplicationController
   private
 
   def group
-    @group ||= Group.find_by(path: params[:id])
+    @group ||= Group.find_by_full_path(params[:id])
   end
 
   def group_params
diff --git a/app/controllers/groups/application_controller.rb b/app/controllers/groups/application_controller.rb
index 949b4a6c25a..c411c21bb80 100644
--- a/app/controllers/groups/application_controller.rb
+++ b/app/controllers/groups/application_controller.rb
@@ -9,7 +9,7 @@ class Groups::ApplicationController < ApplicationController
   def group
     unless @group
       id = params[:group_id] || params[:id]
-      @group = Group.find_by(path: id)
+      @group = Group.find_by_full_path(id)
 
       unless @group && can?(current_user, :read_group, @group)
         @group = nil
diff --git a/app/helpers/groups_helper.rb b/app/helpers/groups_helper.rb
index 19ab059aea6..f6d4ea4659a 100644
--- a/app/helpers/groups_helper.rb
+++ b/app/helpers/groups_helper.rb
@@ -5,7 +5,7 @@ module GroupsHelper
 
   def group_icon(group)
     if group.is_a?(String)
-      group = Group.find_by(path: group)
+      group = Group.find_by_full_path(group)
     end
 
     group.try(:avatar_url) || image_path('no_group_avatar.png')
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
diff --git a/app/models/namespace.rb b/app/models/namespace.rb
index 891dffac648..ff161e4c53f 100644
--- a/app/models/namespace.rb
+++ b/app/models/namespace.rb
@@ -4,12 +4,16 @@ class Namespace < ActiveRecord::Base
   include CacheMarkdownField
   include Sortable
   include Gitlab::ShellAdapter
+  include Routable
 
   cache_markdown_field :description, pipeline: :description
 
   has_many :projects, dependent: :destroy
   belongs_to :owner, class_name: "User"
 
+  belongs_to :parent, class_name: "Namespace"
+  has_many :children, class_name: "Namespace", foreign_key: :parent_id
+
   validates :owner, presence: true, unless: ->(n) { n.type == "Group" }
   validates :name,
     length: { within: 0..255 },
@@ -86,7 +90,7 @@ class Namespace < ActiveRecord::Base
   end
 
   def to_param
-    path
+    full_path
   end
 
   def human_name
@@ -150,6 +154,14 @@ class Namespace < ActiveRecord::Base
     Gitlab.config.lfs.enabled
   end
 
+  def full_path
+    if parent
+      parent.full_path + '/' + path
+    else
+      path
+    end
+  end
+
   private
 
   def repository_storage_paths
@@ -185,4 +197,8 @@ class Namespace < ActiveRecord::Base
       where(projects: { namespace_id: id }).
       find_each(&:refresh_members_authorized_projects)
   end
+
+  def full_path_changed?
+    path_changed? || parent_id_changed?
+  end
 end
diff --git a/app/models/project.rb b/app/models/project.rb
index 9d58aff4033..7659a7bf152 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -14,6 +14,7 @@ class Project < ActiveRecord::Base
   include TokenAuthenticatable
   include ProjectFeaturesCompatibility
   include SelectForProjectAuthorization
+  include Routable
 
   extend Gitlab::ConfigHelper
 
@@ -324,87 +325,6 @@ class Project < ActiveRecord::Base
       non_archived.where(table[:name].matches(pattern))
     end
 
-    # Finds a single project for the given path.
-    #
-    # path - The full project path (including namespace path).
-    #
-    # Returns a Project, or nil if no project could be found.
-    def find_with_namespace(path)
-      namespace_path, project_path = path.split('/', 2)
-
-      return unless namespace_path && project_path
-
-      namespace_path = connection.quote(namespace_path)
-      project_path = connection.quote(project_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} namespaces.path = #{namespace_path} " \
-        "AND #{binary} projects.path = #{project_path} THEN 0 ELSE 1 END)"
-
-      where_paths_in([path]).reorder(order_sql).take
-    end
-
-    # Builds a relation to find multiple projects by their full paths.
-    #
-    # Each path must be in the following format:
-    #
-    #     namespace_path/project_path
-    #
-    # For example:
-    #
-    #     gitlab-org/gitlab-ce
-    #
-    # Usage:
-    #
-    #     Project.where_paths_in(%w{gitlab-org/gitlab-ce gitlab-org/gitlab-ee})
-    #
-    # This would return the projects with the full paths matching the values
-    # given.
-    #
-    # paths - An Array of full paths (namespace path + project path) for which
-    #         to find the projects.
-    #
-    # Returns an ActiveRecord::Relation.
-    def where_paths_in(paths)
-      wheres = []
-      cast_lower = Gitlab::Database.postgresql?
-
-      paths.each do |path|
-        namespace_path, project_path = path.split('/', 2)
-
-        next unless namespace_path && project_path
-
-        namespace_path = connection.quote(namespace_path)
-        project_path = connection.quote(project_path)
-
-        where = "(namespaces.path = #{namespace_path}
-          AND projects.path = #{project_path})"
-
-        if cast_lower
-          where = "(
-            #{where}
-            OR (
-              LOWER(namespaces.path) = LOWER(#{namespace_path})
-              AND LOWER(projects.path) = LOWER(#{project_path})
-            )
-          )"
-        end
-
-        wheres << where
-      end
-
-      if wheres.empty?
-        none
-      else
-        joins(:namespace).where(wheres.join(' OR '))
-      end
-    end
-
     def visibility_levels
       Gitlab::VisibilityLevel.options
     end
@@ -440,6 +360,10 @@ class Project < ActiveRecord::Base
     def group_ids
       joins(:namespace).where(namespaces: { type: 'Group' }).select(:namespace_id)
     end
+
+    # Add alias for Routable method for compatibility with old code.
+    # In future all calls `find_with_namespace` should be replaced with `find_by_full_path`
+    alias_method :find_with_namespace, :find_by_full_path
   end
 
   def lfs_enabled?
@@ -879,13 +803,14 @@ class Project < ActiveRecord::Base
   end
   alias_method :human_name, :name_with_namespace
 
-  def path_with_namespace
-    if namespace
-      namespace.path + '/' + path
+  def full_path
+    if namespace && path
+      namespace.full_path + '/' + path
     else
       path
     end
   end
+  alias_method :path_with_namespace, :full_path
 
   def execute_hooks(data, hooks_scope = :push_hooks)
     hooks.send(hooks_scope).each do |hook|
@@ -1373,4 +1298,8 @@ class Project < ActiveRecord::Base
   def validate_board_limit(board)
     raise BoardLimitExceeded, 'Number of permitted boards exceeded' if boards.size >= NUMBER_OF_PERMITTED_BOARDS
   end
+
+  def full_path_changed?
+    path_changed? || namespace_id_changed?
+  end
 end
diff --git a/app/models/route.rb b/app/models/route.rb
new file mode 100644
index 00000000000..d40214b9da6
--- /dev/null
+++ b/app/models/route.rb
@@ -0,0 +1,22 @@
+class Route < ActiveRecord::Base
+  belongs_to :source, polymorphic: true
+
+  validates :source, presence: true
+
+  validates :path,
+    length: { within: 1..255 },
+    presence: true,
+    uniqueness: { case_sensitive: false }
+
+  after_update :rename_children, if: :path_changed?
+
+  def rename_children
+    # We update each row separately because MySQL does not have regexp_replace.
+    # rubocop:disable Rails/FindEach
+    Route.where('path LIKE ?', "#{path_was}%").each do |route|
+      # Note that update column skips validation and callbacks.
+      # We need this to avoid recursive call of rename_children method
+      route.update_column(:path, route.path.sub(path_was, path))
+    end
+  end
+end
diff --git a/app/services/destroy_group_service.rb b/app/services/destroy_group_service.rb
index a880952e274..2316c57bf1e 100644
--- a/app/services/destroy_group_service.rb
+++ b/app/services/destroy_group_service.rb
@@ -20,6 +20,10 @@ class DestroyGroupService
       ::Projects::DestroyService.new(project, current_user, skip_repo: true).execute
     end
 
+    group.children.each do |group|
+      DestroyGroupService.new(group, current_user).async_execute
+    end
+
     group.really_destroy!
   end
 end
diff --git a/app/views/projects/forks/error.html.haml b/app/views/projects/forks/error.html.haml
index 3d0ab5b85d6..98d81308407 100644
--- a/app/views/projects/forks/error.html.haml
+++ b/app/views/projects/forks/error.html.haml
@@ -13,7 +13,11 @@
     - if @forked_project && @forked_project.errors.any?
       %p
         &ndash;
-        = @forked_project.errors.full_messages.first
+        - error = @forked_project.errors.full_messages.first
+        - if error.include?("already been taken")
+          Name has already been taken
+        - else
+          = error
 
     %p
       = link_to new_namespace_project_fork_path(@project.namespace, @project), title: "Fork", class: "btn" do