refactor `CommandsTasks`

Extract a common method of `Rails::CommandsTasks` and
`Rails::Engine::CommandsTasks` to the module.

1 files changed, 68 insertions, 0 deletions

diff --git a/railties/lib/rails/commands/common_commands_tasks.rb b/railties/lib/rails/commands/common_commands_tasks.rb
new file mode 100644
index 0000000000..c1484d7ae2
--- /dev/null
+++ b/railties/lib/rails/commands/common_commands_tasks.rb
@@ -0,0 +1,68 @@
+module Rails
+  module CommonCommandsTasks # :nodoc:
+    def run_command!(command)
+      command = parse_command(command)
+
+      if command_whitelist.include?(command)
+        send(command)
+      else
+        run_rake_task(command)
+      end
+    end
+
+    def generate
+      generate_or_destroy(:generate)
+    end
+
+    def destroy
+      generate_or_destroy(:destroy)
+    end
+
+    def test
+      require_command!("test")
+    end
+
+    def version
+      argv.unshift "--version"
+      require_command!("application")
+    end
+
+    def help
+      write_help_message
+      write_commands(commands)
+    end
+
+    private
+
+      def generate_or_destroy(command)
+        require "rails/generators"
+        require_application_and_environment!
+        load_generators
+        require_command!(command)
+      end
+
+      def require_command!(command)
+        require "rails/commands/#{command}"
+      end
+
+      def write_help_message
+        puts help_message
+      end
+
+      def write_commands(commands)
+        width = commands.map { |name, _| name.size }.max || 10
+        commands.each { |command| printf(" %-#{width}s   %s\n", *command) }
+      end
+
+      def parse_command(command)
+        case command
+        when "--version", "-v"
+          "version"
+        when "--help", "-h"
+          "help"
+        else
+          command
+        end
+      end
+  end
+end