erubi.rb

# frozen_string_literal: true

require "erubi"

module ActionView
  class Template
    module Handlers
      class ERB
        class Erubi < ::Erubi::Engine
          # :nodoc: all
          def initialize(input, properties = {})
            @newline_pending = 0

            # Dup properties so that we don't modify argument
            properties = Hash[properties]

            properties[:preamble]   ||= ""
            properties[:postamble]  ||= "@output_buffer.to_s"

            properties[:bufvar]     = "@output_buffer"
            properties[:escapefunc] = ""

            super
          end

          def evaluate(action_view_erb_handler_context)
            src = @src
            view = Class.new(ActionView::Base) {
              include action_view_erb_handler_context._routes.url_helpers
              class_eval("define_method(:_template) { |local_assigns, output_buffer| #{src} }", defined?(@filename) ? @filename : "(erubi)", 0)
            }.empty
            view._run(:_template, nil, {}, ActionView::OutputBuffer.new)
          end

        private
          def add_text(text)
            return if text.empty?

            if text == "\n"
              @newline_pending += 1
            else
              src << "@output_buffer.safe_append='"
              src << "\n" * @newline_pending if @newline_pending > 0
              src << text.gsub(/['\\]/, '\\\\\&')
              src << "'.freeze;"

              @newline_pending = 0
            end
          end

          BLOCK_EXPR = /\s*((\s+|\))do|\{)(\s*\|[^|]*\|)?\s*\Z/

          def add_expression(indicator, code)
            flush_newline_if_pending(src)

            if (indicator == "==") || @escape
              src << "@output_buffer.safe_expr_append="
            else
              src << "@output_buffer.append="
            end

            if BLOCK_EXPR.match?(code)
              src << " " << code
            else
              src << "(" << code << ");"
            end
          end

          def add_code(code)
            flush_newline_if_pending(src)
            super
          end

          def add_postamble(_)
            flush_newline_if_pending(src)
            super
          end

          def flush_newline_if_pending(src)
            if @newline_pending > 0
              src << "@output_buffer.safe_append='#{"\n" * @newline_pending}'.freeze;"
              @newline_pending = 0
            end
          end
        end
      end
    end
  end
end