Implement Shadow DOM API

This adds new method `Element#shadow_root` which returns an instance of
`ShadowRoot` class. It can then be used to locate elements within this
shadow root.

Note that currently no drivers support WebDriver's Shadow DOM API.
Consider this implementation a draft because there was no way to test
it.

Author: p0deje

rb/lib/selenium/webdriver/common.rb

@@ -75,3 +75,4 @@
 require 'selenium/webdriver/common/takes_screenshot'
 require 'selenium/webdriver/common/driver'
 require 'selenium/webdriver/common/element'
+require 'selenium/webdriver/common/shadow_root'

rb/lib/selenium/webdriver/common/driver.rb

@@ -297,7 +297,9 @@ def capabilities
       # @see SearchContext
       #
 
-      def ref; end
+      def ref
+        [:driver, nil]
+      end
 
       private
 

rb/lib/selenium/webdriver/common/element.rb

@@ -143,7 +143,7 @@ def attribute(name)
       #
 
       def dom_attribute(name)
-        bridge.element_dom_attribute self, name
+        bridge.element_dom_attribute @id, name
       end
 
       #
@@ -157,7 +157,7 @@ def dom_attribute(name)
       #
 
       def property(name)
-        bridge.element_property self, name
+        bridge.element_property @id, name
       end
 
       #
@@ -167,7 +167,7 @@ def property(name)
       #
 
       def aria_role
-        bridge.element_aria_role self
+        bridge.element_aria_role @id
       end
 
       #
@@ -177,7 +177,7 @@ def aria_role
       #
 
       def accessible_name
-        bridge.element_aria_label self
+        bridge.element_aria_label @id
       end
 
       #
@@ -317,6 +317,16 @@ def size
         bridge.element_size @id
       end
 
+      #
+      # Returns the shadow root of an element.
+      #
+      # @return [WebDriver::ShadowRoot]
+      #
+
+      def shadow_root
+        bridge.shadow_root @id
+      end
+
       #-------------------------------- sugar  --------------------------------
 
       #
@@ -336,14 +346,13 @@ def size
       #
       alias_method :[], :attribute
 
-      #
-      # for SearchContext and execute_script
       #
       # @api private
+      # @see SearchContext
       #
 
       def ref
-        @id
+        [:element, @id]
       end
 
       #
@@ -379,7 +388,7 @@ def selectable?
       end
 
       def screenshot
-        bridge.element_screenshot(self)
+        bridge.element_screenshot(@id)
       end
     end # Element
   end # WebDriver

rb/lib/selenium/webdriver/common/error.rb

@@ -61,6 +61,12 @@ class UnknownCommandError < WebDriverError; end
 
       class StaleElementReferenceError < WebDriverError; end
 
+      #
+      # A command failed because the referenced shadow root is no longer attached to the DOM.
+      #
+
+      class DetachedShadowRootError < WebDriverError; end
+
       #
       # The target element is in an invalid state, rendering it impossible to interact with, for
       # example if you click a disabled element.
@@ -93,6 +99,12 @@ class TimeoutError < WebDriverError; end
 
       class NoSuchWindowError < WebDriverError; end
 
+      #
+      # The element does not have a shadow root.
+      #
+
+      class NoSuchShadowRootError < WebDriverError; end
+
       #
       # An illegal attempt was made to set a cookie under a different domain than the current page.
       #

rb/lib/selenium/webdriver/common/shadow_root.rb

@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+# Licensed to the Software Freedom Conservancy (SFC) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The SFC licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+module Selenium
+  module WebDriver
+    class ShadowRoot
+      ROOT_KEY = 'shadow-6066-11e4-a52e-4f735466cecf'
+
+      include SearchContext
+
+      #
+      # Creates a new shadow root
+      #
+      # @api private
+      #
+
+      def initialize(bridge, id)
+        @bridge = bridge
+        @id = id
+      end
+
+      def inspect
+        format '#<%<class>s:0x%<hash>x id=%<id>s>', class: self.class, hash: hash * 2, id: @id.inspect
+      end
+
+      def ==(other)
+        other.is_a?(self.class) && ref == other.ref
+      end
+      alias_method :eql?, :==
+
+      def hash
+        @id.hash ^ @bridge.hash
+      end
+
+      #
+      # @api private
+      # @see SearchContext
+      #
+
+      def ref
+        [:shadow_root, @id]
+      end
+
+      #
+      # Convert to a ShadowRoot JSON Object for transmission over the wire.
+      # @see https://github.com/SeleniumHQ/selenium/wiki/JsonWireProtocol#basic-terms-and-concepts
+      #
+      # @api private
+      #
+
+      def to_json(*)
+        JSON.generate as_json
+      end
+
+      #
+      # For Rails 3 - http://jonathanjulian.com/2010/04/rails-to_json-or-as_json/
+      #
+      # @api private
+      #
+
+      def as_json(*)
+        {ROOT_KEY => @id}
+      end
+
+      private
+
+      attr_reader :bridge
+
+    end # ShadowRoot
+  end # WebDriver
+end # Selenium

rb/lib/selenium/webdriver/remote/bridge.rb

@@ -269,7 +269,7 @@ def screenshot
         end
 
         def element_screenshot(element)
-          execute :take_element_screenshot, id: element.ref
+          execute :take_element_screenshot, id: element
         end
 
         #
@@ -431,7 +431,7 @@ def clear_element(element)
         end
 
         def submit_element(element)
-          form = find_element_by('xpath', "./ancestor-or-self::form", element)
+          form = find_element_by('xpath', "./ancestor-or-self::form", [:element, element])
           execute_script("var e = arguments[0].ownerDocument.createEvent('Event');" \
                             "e.initEvent('submit', true, true);" \
                             'if (arguments[0].dispatchEvent(e)) { arguments[0].submit() }', form.as_json)
@@ -451,19 +451,19 @@ def element_attribute(element, name)
         end
 
         def element_dom_attribute(element, name)
-          execute :get_element_attribute, id: element.ref, name: name
+          execute :get_element_attribute, id: element, name: name
         end
 
         def element_property(element, name)
-          execute :get_element_property, id: element.ref, name: name
+          execute :get_element_property, id: element, name: name
         end
 
         def element_aria_role(element)
-          execute :get_element_aria_role, id: element.ref
+          execute :get_element_aria_role, id: element
         end
 
         def element_aria_label(element)
-          execute :get_element_aria_label, id: element.ref
+          execute :get_element_aria_label, id: element
         end
 
         def element_value(element)
@@ -524,34 +524,47 @@ def active_element
 
         alias_method :switch_to_active_element, :active_element
 
-        def find_element_by(how, what, parent = nil)
+        def find_element_by(how, what, parent_ref = [])
           how, what = convert_locator(how, what)
 
           return execute_atom(:findElements, Support::RelativeLocator.new(what).as_json).first if how == 'relative'
 
-          id = if parent
-                 execute :find_child_element, {id: parent}, {using: how, value: what.to_s}
+          parent_type, parent_id = parent_ref
+          id = case parent_type
+               when :element
+                 execute :find_child_element, {id: parent_id}, {using: how, value: what.to_s}
+               when :shadow_root
+                 execute :find_shadow_child_element, {id: parent_id}, {using: how, value: what.to_s}
                else
                  execute :find_element, {}, {using: how, value: what.to_s}
                end
 
           Element.new self, element_id_from(id)
         end
 
-        def find_elements_by(how, what, parent = nil)
+        def find_elements_by(how, what, parent_ref = [])
           how, what = convert_locator(how, what)
 
           return execute_atom :findElements, Support::RelativeLocator.new(what).as_json if how == 'relative'
 
-          ids = if parent
-                  execute :find_child_elements, {id: parent}, {using: how, value: what.to_s}
+          parent_type, parent_id = parent_ref
+          ids = case parent_type
+                when :element
+                  execute :find_child_elements, {id: parent_id}, {using: how, value: what.to_s}
+                when :shadow_root
+                  execute :find_shadow_child_elements, {id: parent_id}, {using: how, value: what.to_s}
                 else
                   execute :find_elements, {}, {using: how, value: what.to_s}
                 end
 
           ids.map { |id| Element.new self, element_id_from(id) }
         end
 
+        def shadow_root(element)
+          id = execute :get_element_shadow_root, id: element
+          ShadowRoot.new self, shadow_root_id_from(id)
+        end
+
         private
 
         #
@@ -599,7 +612,11 @@ def unwrap_script_result(arg)
         end
 
         def element_id_from(id)
-          id['ELEMENT'] || id['element-6066-11e4-a52e-4f735466cecf']
+          id['ELEMENT'] || id[Element::ELEMENT_KEY]
+        end
+
+        def shadow_root_id_from(id)
+          id[ShadowRoot::ROOT_KEY]
         end
 
         def prepare_capabilities_payload(capabilities)

rb/lib/selenium/webdriver/remote/commands.rb

@@ -77,7 +77,10 @@ class Bridge
           find_elements: [:post, 'session/:session_id/elements'],
           find_child_element: [:post, 'session/:session_id/element/:id/element'],
           find_child_elements: [:post, 'session/:session_id/element/:id/elements'],
+          find_shadow_child_element: [:post, 'session/:session_id/shadow/:id/element'],
+          find_shadow_child_elements: [:post, 'session/:session_id/shadow/:id/elements'],
           get_active_element: [:get, 'session/:session_id/element/active'],
+          get_element_shadow_root: [:get, 'session/:session_id/element/:id/shadow'],
           is_element_selected: [:get, 'session/:session_id/element/:id/selected'],
           get_element_attribute: [:get, 'session/:session_id/element/:id/attribute/:name'],
           get_element_property: [:get, 'session/:session_id/element/:id/property/:name'],

rb/lib/selenium/webdriver/support/event_firing_bridge.rb

@@ -76,15 +76,15 @@ def find_element_by(how, what, parent = nil)
             @delegate.find_element_by how, what, parent
           end
 
-          Element.new self, e.ref
+          Element.new self, e.ref.last
         end
 
         def find_elements_by(how, what, parent = nil)
           es = dispatch(:find, how, what, driver) do
             @delegate.find_elements_by(how, what, parent)
           end
 
-          es.map { |e| Element.new self, e.ref }
+          es.map { |e| Element.new self, e.ref.last }
         end
 
         def execute_script(script, *args)

rb/spec/unit/selenium/webdriver/support/event_firing_spec.rb

@@ -62,20 +62,20 @@ module Support
         context 'finding elements' do
           it 'fires events for find_element' do
             expect(listener).to receive(:before_find).with('id', 'foo', instance_of(Driver))
-            allow(bridge).to receive(:find_element_by).with('id', 'foo', nil).and_return(element)
+            allow(bridge).to receive(:find_element_by).with('id', 'foo', [:driver, nil]).and_return(element)
             expect(listener).to receive(:after_find).with('id', 'foo', instance_of(Driver))
 
             driver.find_element(id: 'foo')
-            expect(bridge).to have_received(:find_element_by).with('id', 'foo', nil)
+            expect(bridge).to have_received(:find_element_by).with('id', 'foo', [:driver, nil])
           end
 
           it 'fires events for find_elements' do
             expect(listener).to receive(:before_find).with('class name', 'foo', instance_of(Driver))
-            allow(bridge).to receive(:find_elements_by).with('class name', 'foo', nil).and_return([element])
+            allow(bridge).to receive(:find_elements_by).with('class name', 'foo', [:driver, nil]).and_return([element])
             expect(listener).to receive(:after_find).with('class name', 'foo', instance_of(Driver))
 
             driver.find_elements(class: 'foo')
-            expect(bridge).to have_received(:find_elements_by).with('class name', 'foo', nil)
+            expect(bridge).to have_received(:find_elements_by).with('class name', 'foo', [:driver, nil])
           end
         end