Merge branch '23563-document-presenters' into 'master'

Document presenters

Closes #23563

See merge request !8480

4 files changed, 88 insertions, 0 deletions

diff --git a/lib/gitlab/view/presenter/base.rb b/lib/gitlab/view/presenter/base.rb
new file mode 100644
index 00000000000..83c8ba5c1cf
--- /dev/null
+++ b/lib/gitlab/view/presenter/base.rb
@@ -0,0 +1,28 @@
+module Gitlab
+  module View
+    module Presenter
+      module Base
+        extend ActiveSupport::Concern
+
+        include Gitlab::Routing
+        include Gitlab::Allowable
+
+        attr_reader :subject
+
+        def can?(user, action, overriden_subject = nil)
+          super(user, action, overriden_subject || subject)
+        end
+
+        class_methods do
+          def presenter?
+            true
+          end
+
+          def presents(name)
+            define_method(name) { subject }
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/view/presenter/delegated.rb b/lib/gitlab/view/presenter/delegated.rb
new file mode 100644
index 00000000000..f4d330c590e
--- /dev/null
+++ b/lib/gitlab/view/presenter/delegated.rb
@@ -0,0 +1,19 @@
+module Gitlab
+  module View
+    module Presenter
+      class Delegated < SimpleDelegator
+        include Gitlab::View::Presenter::Base
+
+        def initialize(subject, **attributes)
+          @subject = subject
+
+          attributes.each do |key, value|
+            define_singleton_method(key) { value }
+          end
+
+          super(subject)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/view/presenter/factory.rb b/lib/gitlab/view/presenter/factory.rb
new file mode 100644
index 00000000000..d172d61e2c9
--- /dev/null
+++ b/lib/gitlab/view/presenter/factory.rb
@@ -0,0 +1,24 @@
+module Gitlab
+  module View
+    module Presenter
+      class Factory
+        def initialize(subject, **attributes)
+          @subject = subject
+          @attributes = attributes
+        end
+
+        def fabricate!
+          presenter_class.new(subject, attributes)
+        end
+
+        private
+
+        attr_reader :subject, :attributes
+
+        def presenter_class
+          "#{subject.class.name}Presenter".constantize
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/view/presenter/simple.rb b/lib/gitlab/view/presenter/simple.rb
new file mode 100644
index 00000000000..b7653a0f3cc
--- /dev/null
+++ b/lib/gitlab/view/presenter/simple.rb
@@ -0,0 +1,17 @@
+module Gitlab
+  module View
+    module Presenter
+      class Simple
+        include Gitlab::View::Presenter::Base
+
+        def initialize(subject, **attributes)
+          @subject = subject
+
+          attributes.each do |key, value|
+            define_singleton_method(key) { value }
+          end
+        end
+      end
+    end
+  end
+end