Merge bundler to standard libraries.

rubygems 2.7.x depends bundler-1.15.x. This is preparation for
  rubygems and bundler migration.

  * lib/bundler.rb, lib/bundler/*: files of bundler-1.15.4
  * spec/bundler/*: rspec examples of bundler-1.15.4. I applied patches.
    * https://github.com/bundler/bundler/pull/6007
    * Exclude not working examples on ruby repository.
    * Fake ruby interpriter instead of installed ruby.
  * Makefile.in: Added test task named `test-bundler`. This task is only
    working macOS/linux yet. I'm going to support Windows environment later.
  * tool/sync_default_gems.rb: Added sync task for bundler.

  [Feature #12733][ruby-core:77172]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59779 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/bundler/ui/shell.rb

@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+require "bundler/vendored_thor"
+
+module Bundler
+  module UI
+    class Shell
+      LEVELS = %w(silent error warn confirm info debug).freeze
+
+      attr_writer :shell
+
+      def initialize(options = {})
+        if options["no-color"] || !STDOUT.tty?
+          Thor::Base.shell = Thor::Shell::Basic
+        end
+        @shell = Thor::Base.shell.new
+        @level = ENV["DEBUG"] ? "debug" : "info"
+        @warning_history = []
+      end
+
+      def add_color(string, *color)
+        @shell.set_color(string, *color)
+      end
+
+      def info(msg, newline = nil)
+        tell_me(msg, nil, newline) if level("info")
+      end
+
+      def confirm(msg, newline = nil)
+        tell_me(msg, :green, newline) if level("confirm")
+      end
+
+      def warn(msg, newline = nil)
+        return if @warning_history.include? msg
+        @warning_history << msg
+        tell_me(msg, :yellow, newline) if level("warn")
+      end
+
+      def error(msg, newline = nil)
+        tell_me(msg, :red, newline) if level("error")
+      end
+
+      def debug(msg, newline = nil)
+        tell_me(msg, nil, newline) if debug?
+      end
+
+      def debug?
+        level("debug")
+      end
+
+      def quiet?
+        level("quiet")
+      end
+
+      def ask(msg)
+        @shell.ask(msg)
+      end
+
+      def yes?(msg)
+        @shell.yes?(msg)
+      end
+
+      def no?
+        @shell.no?(msg)
+      end
+
+      def level=(level)
+        raise ArgumentError unless LEVELS.include?(level.to_s)
+        @level = level.to_s
+      end
+
+      def level(name = nil)
+        return @level unless name
+        unless index = LEVELS.index(name)
+          raise "#{name.inspect} is not a valid level"
+        end
+        index <= LEVELS.index(@level)
+      end
+
+      def trace(e, newline = nil, force = false)
+        return unless debug? || force
+        msg = "#{e.class}: #{e.message}\n#{e.backtrace.join("\n  ")}"
+        tell_me(msg, nil, newline)
+      end
+
+      def silence(&blk)
+        with_level("silent", &blk)
+      end
+
+      def unprinted_warnings
+        []
+      end
+
+    private
+
+      # valimism
+      def tell_me(msg, color = nil, newline = nil)
+        msg = word_wrap(msg) if newline.is_a?(Hash) && newline[:wrap]
+        if newline.nil?
+          @shell.say(msg, color)
+        else
+          @shell.say(msg, color, newline)
+        end
+      end
+
+      def tell_err(message, color = nil, newline = nil)
+        buffer = @shell.send(:prepare_message, message, *color)
+        buffer << "\n" if newline && !message.to_s.end_with?("\n")
+
+        @shell.send(:stderr).print(buffer)
+        @shell.send(:stderr).flush
+      end
+
+      def strip_leading_spaces(text)
+        spaces = text[/\A\s+/, 0]
+        spaces ? text.gsub(/#{spaces}/, "") : text
+      end
+
+      def word_wrap(text, line_width = @shell.terminal_width)
+        strip_leading_spaces(text).split("\n").collect do |line|
+          line.length > line_width ? line.gsub(/(.{1,#{line_width}})(\s+|$)/, "\\1\n").strip : line
+        end * "\n"
+      end
+
+      def with_level(level)
+        original = @level
+        @level = level
+        yield
+      ensure
+        @level = original
+      end
+    end
+  end
+end