class DEBUGGER__::Session

# File debug-1.4.0/lib/debug/session.rb, line 85
def initialize ui
  @ui = ui
  @sr = SourceRepository.new
  @bps = {} # bp.key => bp
            #   [file, line] => LineBreakpoint
            #   "Error" => CatchBreakpoint
            #   "Foo#bar" => MethodBreakpoint
            #   [:watch, ivar] => WatchIVarBreakpoint
            #   [:check, expr] => CheckBreakpoint
  #
  @tracers = {}
  @th_clients = {} # {Thread => ThreadClient}
  @q_evt = Queue.new
  @displays = []
  @tc = nil
  @tc_id = 0
  @preset_command = nil
  @postmortem_hook = nil
  @postmortem = false
  @intercept_trap_sigint = false
  @intercepted_sigint_cmd = 'DEFAULT'
  @process_group = ProcessGroup.new
  @subsession = nil

  @frame_map = {} # for DAP: {id => [threadId, frame_depth]} and CDP: {id => frame_depth}
  @var_map   = {1 => [:globals], } # {id => ...} for DAP
  @src_map   = {} # {id => src}

  @script_paths = [File.absolute_path($0)] # for CDP
  @obj_map = {} # { object_id => ... } for CDP

  @tp_thread_begin = nil
  @tp_load_script = TracePoint.new(:script_compiled){|tp|
    ThreadClient.current.on_load tp.instruction_sequence, tp.eval_script
  }
  @tp_load_script.enable

  @thread_stopper = thread_stopper

  activate

  self.postmortem = CONFIG[:postmortem]
end

# File debug-1.4.0/lib/debug/session.rb, line 137
def activate on_fork: false
  @tp_thread_begin&.disable
  @tp_thread_begin = nil

  if on_fork
    @ui.activate self, on_fork: true
  else
    @ui.activate self, on_fork: false
  end

  q = Queue.new
  @session_server = Thread.new do
    Thread.current.name = 'DEBUGGER__::SESSION@server'
    Thread.current.abort_on_exception = true

    # Thread management
    setup_threads
    thc = get_thread_client Thread.current
    thc.mark_as_management

    if @ui.respond_to?(:reader_thread) && thc = get_thread_client(@ui.reader_thread)
      thc.mark_as_management
    end

    @tp_thread_begin = TracePoint.new(:thread_begin) do |tp|
      get_thread_client
    end
    @tp_thread_begin.enable

    # session start
    q << true
    session_server_main
  end

  q.pop
end

# File debug-1.4.0/lib/debug/session.rb, line 129
def active?
  !@q_evt.closed?
end

# File debug-1.4.0/lib/debug/session.rb, line 1232
def add_bp bp
  # don't repeat commands that add breakpoints
  @repl_prev_line = nil

  if @bps.has_key? bp.key
    unless bp.duplicable?
      @ui.puts "duplicated breakpoint: #{bp}"
      bp.disable
    end
  else
    @bps[bp.key] = bp
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1320
def add_catch_breakpoint pat
  bp = CatchBreakpoint.new(pat)
  add_bp bp
end

# File debug-1.4.0/lib/debug/session.rb, line 1325
def add_check_breakpoint expr, path
  bp = CheckBreakpoint.new(expr, path)
  add_bp bp
end

# File debug-1.4.0/lib/debug/session.rb, line 1339
def add_iseq_breakpoint iseq, **kw
  bp = ISeqBreakpoint.new(iseq, [:line], **kw)
  add_bp bp
end

# File debug-1.4.0/lib/debug/session.rb, line 1330
def add_line_breakpoint file, line, **kw
  file = resolve_path(file)
  bp = LineBreakpoint.new(file, line, **kw)

  add_bp bp
rescue Errno::ENOENT => e
  @ui.puts e.message
end

# File debug-1.4.0/lib/debug/session.rb, line 300
def add_preset_commands name, cmds, kick: true, continue: true
  cs = cmds.map{|c|
    c.each_line.map{|line|
      line = line.strip.gsub(/\A\s*\#.*/, '').strip
      line unless line.empty?
    }.compact
  }.flatten.compact

  if @preset_command && !@preset_command.commands.empty?
    @preset_command.commands += cs
  else
    @preset_command = PresetCommand.new(cs, name, continue)
  end

  ThreadClient.current.on_init name if kick
end

# File debug-1.4.0/lib/debug/session.rb, line 1346
def add_tracer tracer
  # don't repeat commands that add tracers
  @repl_prev_line = nil
  if @tracers.has_key? tracer.key
    tracer.disable
    @ui.puts "Duplicated tracer: #{tracer}"
  else
    @tracers[tracer.key] = tracer
    @ui.puts "Enable #{tracer}"
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1717
def after_fork_parent
  @ui.after_fork_parent
end

# File debug-1.4.0/lib/debug/session.rb, line 1174
def ask msg, default = 'Y'
  opts = '[y/n]'.tr(default.downcase, default)
  input = @ui.ask("#{msg} #{opts} ")
  input = default if input.empty?
  case input
  when 'y', 'Y'
    true
  else
    false
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1711
def before_fork need_lock = true
  if need_lock
    @process_group.multi_process!
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1209
def bp_index specific_bp_key
  iterate_bps do |key, bp, i|
    if key == specific_bp_key
      return [bp, i]
    end
  end
  nil
end

# File debug-1.4.0/lib/debug/session.rb, line 133
def break_at? file, line
  @bps.has_key? [file, line]
end

# File debug-1.4.0/lib/debug/session.rb, line 1156
def cancel_auto_continue
  if @preset_command&.auto_continue
    @preset_command.auto_continue = false
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1608
def capture_exception_frames *exclude_path
  postmortem_hook = TracePoint.new(:raise){|tp|
    exc = tp.raised_exception
    frames = DEBUGGER__.capture_frames(__dir__)

    exclude_path.each{|ex|
      if Regexp === ex
        frames.delete_if{|e| ex =~ e.path}
      else
        frames.delete_if{|e| e.path.start_with? ex.to_s}
      end
    }
    exc.instance_variable_set(:@__debugger_postmortem_frames, frames)
  }
  postmortem_hook.enable

  begin
    yield
    nil
  rescue Exception => e
    if e.instance_variable_defined? :@__debugger_postmortem_frames
      e
    else
      raise
    end
  ensure
    postmortem_hook.disable
  end
end

# File debug-1.4.0/lib/debug/server_cdp.rb, line 560
def cdp_event args
  type, req, result = args

  case type
  when :backtrace
    result[:callFrames].each.with_index do |frame, i|
      frame_id = frame[:callFrameId]
      @frame_map[frame_id] = i
      s_id = frame.dig(:location, :scriptId)
      if File.exist?(s_id) && !@script_paths.include?(s_id)
        src = File.read(s_id)
        @ui.fire_event 'Debugger.scriptParsed',
                        scriptId: s_id,
                        url: frame[:url],
                        startLine: 0,
                        startColumn: 0,
                        endLine: src.count("\n"),
                        endColumn: 0,
                        executionContextId: @script_paths.size + 1,
                        hash: src.hash
        @script_paths << s_id
      end

      frame[:scopeChain].each {|s|
        oid = s.dig(:object, :objectId)
        @obj_map[oid] = [s[:type], frame_id]
      }
    end

    if oid = result.dig(:data, :objectId)
      @obj_map[oid] = ['properties']
    end
    @ui.fire_event 'Debugger.paused', **result
  when :evaluate
    message = result.delete :message
    if message
      fail_response req,
                    code: INVALID_PARAMS,
                    message: message
    else
      rs = result.dig(:response, :result)
      [rs].each{|obj|
        if oid = obj[:objectId]
          @obj_map[oid] = ['properties']
        end
      }
      @ui.respond req, **result[:response]

      out = result[:output]
      if out && !out.empty?
        @ui.fire_event 'Runtime.consoleAPICalled',
                        type: 'log',
                        args: [
                          type: out.class,
                          value: out
                        ],
                        executionContextId: 1, # Change this number if something goes wrong.
                        timestamp: Time.now.to_f
      end
    end
  when :scope
    result.each{|obj|
      if oid = obj.dig(:value, :objectId)
        @obj_map[oid] = ['properties']
      end
    }
    @ui.respond req, result: result
  when :properties
    result.each_value{|v|
      v.each{|obj|
        if oid = obj.dig(:value, :objectId)
          @obj_map[oid] = ['properties']
        end
      }
    }
    @ui.respond req, **result
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1592
def check_postmortem
  if @postmortem
    raise PostmortemError, "Can not use this command on postmortem mode."
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1226
def clean_bps
  @bps.delete_if{|_k, bp|
    bp.deleted?
  }
end

# File debug-1.4.0/lib/debug/session.rb, line 1122
def config_command arg
  case arg
  when nil
    CONFIG_SET.each do |k, _|
      config_show k
    end

  when /\Aunset\s+(.+)\z/
    if CONFIG_SET[key = $1.to_sym]
      CONFIG[key] = nil
    end
    config_show key

  when /\A(\w+)\s*=\s*(.+)\z/
    config_set $1, $2

  when /\A\s*set\s+(\w+)\s+(.+)\z/
    config_set $1, $2

  when /\A(\w+)\s*<<\s*(.+)\z/
    config_set $1, $2, append: true

  when /\A\s*append\s+(\w+)\s+(.+)\z/
    config_set $1, $2

  when /\A(\w+)\z/
    config_show $1

  else
    @ui.puts "Can not parse parameters: #{arg}"
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1106
def config_set key, val, append: false
  if CONFIG_SET[key = key.to_sym]
    begin
      if append
        CONFIG.append_config(key, val)
      else
        CONFIG[key] = val
      end
    rescue => e
      @ui.puts e.message
    end
  end

  config_show key
end

# File debug-1.4.0/lib/debug/session.rb, line 1089
def config_show key
  key = key.to_sym
  if CONFIG_SET[key]
    v = CONFIG[key]
    kv = "#{key} = #{v.nil? ? '(default)' : v.inspect}"
    desc = CONFIG_SET[key][1]
    line = "%-30s \# %s" % [kv, desc]
    if line.size > SESSION.width
      @ui.puts "\# #{desc}\n#{kv}"
    else
      @ui.puts line
    end
  else
    @ui.puts "Unknown configuration: #{key}. 'config' shows all configurations."
  end
end

# File debug-1.4.0/lib/debug/server_dap.rb, line 524
def dap_event args
  # puts({dap_event: args}.inspect)
  type, req, result = args

  case type
  when :backtrace
    result[:stackFrames].each.with_index{|fi, i|
      fi[:id] = id = @frame_map.size + 1
      @frame_map[id] = [req.dig('arguments', 'threadId'), i]
      if fi[:source] && src = fi[:source][:sourceReference]
        src_id = @src_map.size + 1
        @src_map[src_id] = src
        fi[:source][:sourceReference] = src_id
      end
    }
    @ui.respond req, result
  when :scopes
    frame_id = req.dig('arguments', 'frameId')
    local_scope = result[:scopes].first
    local_scope[:variablesReference] = id = @var_map.size + 1

    @var_map[id] = [:scope, frame_id]
    @ui.respond req, result
  when :scope
    tid = result.delete :tid
    register_vars result[:variables], tid
    @ui.respond req, result
  when :variable
    tid = result.delete :tid
    register_vars result[:variables], tid
    @ui.respond req, result
  when :evaluate
    message = result.delete :message
    if message
      @ui.respond req, success: false, message: message
    else
      tid = result.delete :tid
      register_var result, tid
      @ui.respond req, result
    end
  when :completions
    @ui.respond req, result
  else
    raise "unsupported: #{args.inspect}"
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 174
def deactivate
  get_thread_client.deactivate
  @thread_stopper.disable
  @tp_load_script.disable
  @tp_thread_begin.disable
  @bps.each_value{|bp| bp.disable}
  @th_clients.each_value{|thc| thc.close}
  @tracers.values.each{|t| t.disable}
  @q_evt.close
  @ui&.deactivate
  @ui = nil
end

# File debug-1.4.0/lib/debug/session.rb, line 1246
def delete_bp arg = nil
  case arg
  when nil
    @bps.each{|key, bp| bp.delete}
    @bps.clear
  else
    del_bp = nil
    iterate_bps{|key, bp, i| del_bp = bp if i == arg}
    if del_bp
      del_bp.delete
      @bps.delete del_bp.key
      return [arg, del_bp]
    end
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1598
def enter_postmortem_session exc
  return unless exc.instance_variable_defined? :@__debugger_postmortem_frames

  frames = exc.instance_variable_get(:@__debugger_postmortem_frames)
  @postmortem = true
  ThreadClient.current.suspend :postmortem, postmortem_frames: frames, postmortem_exc: exc
ensure
  @postmortem = false
end

# File debug-1.4.0/lib/debug/server_cdp.rb, line 514
def fail_response req, **result
  @ui.respond_fail req, result
  return :retry
end

# File debug-1.4.0/lib/debug/server_dap.rb, line 397
def find_waiting_tc id
  @th_clients.each{|th, tc|
    return tc if tc.id == id && tc.waiting?
  }
  return nil
end

# File debug-1.4.0/lib/debug/session.rb, line 1448
def get_thread_client th = Thread.current
  if @th_clients.has_key? th
    @th_clients[th]
  else
    if Thread.current == @session_server
      create_thread_client th
    else
      ask_thread_client th
    end
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1525
def in_subsession?
  @subsession
end

# File debug-1.4.0/lib/debug/session.rb, line 325
def inspect
  "DEBUGGER__::SESSION"
end

# File debug-1.4.0/lib/debug/session.rb, line 1686
def intercept_trap_sigint flag, &b
  prev = @intercept_trap_sigint
  @intercept_trap_sigint = flag
  yield
ensure
  @intercept_trap_sigint = prev
end

# File debug-1.4.0/lib/debug/session.rb, line 1682
def intercept_trap_sigint?
  @intercept_trap_sigint
end

# File debug-1.4.0/lib/debug/session.rb, line 1699
def intercept_trap_sigint_end
  @intercept_trap_sigint = false
  prev, @intercepted_sigint_cmd = @intercepted_sigint_cmd, nil
  prev
end

# File debug-1.4.0/lib/debug/session.rb, line 1694
def intercept_trap_sigint_start prev
  @intercept_trap_sigint = true
  @intercepted_sigint_cmd = prev
end

# File debug-1.4.0/lib/debug/session.rb, line 1188
def iterate_bps
  deleted_bps = []
  i = 0
  @bps.each{|key, bp|
    if !bp.deleted?
      yield key, bp, i
      i += 1
    else
      deleted_bps << bp
    end
  }
ensure
  deleted_bps.each{|bp| @bps.delete bp}
end

# File debug-1.4.0/lib/debug/session.rb, line 1392
def managed_thread_clients
  thcs, _unmanaged_ths = update_thread_list
  thcs
end

# File debug-1.4.0/lib/debug/session.rb, line 1564
def method_added tp
  b = tp.binding
  if var_name = b.local_variables.first
    mid = b.local_variable_get(var_name)
    unresolved = false

    @bps.each{|k, bp|
      case bp
      when MethodBreakpoint
        if bp.method.nil?
          if bp.sig_method_name == mid.to_s
            bp.try_enable(added: true)
          end
        end

        unresolved = true unless bp.enabled?
      end
    }
    unless unresolved
      METHOD_ADDED_TRACKER.disable
    end
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1531
def on_load iseq, src
  DEBUGGER__.info "Load #{iseq.absolute_path || iseq.path}"
  @sr.add iseq, src

  pending_line_breakpoints = @bps.find_all do |key, bp|
    LineBreakpoint === bp && !bp.iseq
  end

  pending_line_breakpoints.each do |_key, bp|
    if bp.path == (iseq.absolute_path || iseq.path)
      bp.try_activate
    end
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1423
def on_thread_begin th
  if @th_clients.has_key? th
    # TODO: NG?
  else
    create_thread_client th
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1264
def parse_break arg
  mode = :sig
  expr = Hash.new{|h, k| h[k] = []}
  arg.split(' ').each{|w|
    if BREAK_KEYWORDS.any?{|pat| w == pat}
      mode = w[0..-2].to_sym
    else
      expr[mode] << w
    end
  }
  expr.default_proc = nil
  expr.transform_values{|v| v.join(' ')}
end

# File debug-1.4.0/lib/debug/session.rb, line 192
def pop_event
  @q_evt.pop
end

# File debug-1.4.0/lib/debug/session.rb, line 1638
def postmortem=(is_enable)
  if is_enable
    unless @postmortem_hook
      @postmortem_hook = TracePoint.new(:raise){|tp|
        exc = tp.raised_exception
        frames = DEBUGGER__.capture_frames(__dir__)
        exc.instance_variable_set(:@__debugger_postmortem_frames, frames)
      }
      at_exit{
        @postmortem_hook.disable
        if CONFIG[:postmortem] && (exc = $!) != nil
          exc = exc.cause while exc.cause

          begin
            @ui.puts "Enter postmortem mode with #{exc.inspect}"
            @ui.puts exc.backtrace.map{|e| '  ' + e}
            @ui.puts "\n"

            enter_postmortem_session exc
          rescue SystemExit
            exit!
          rescue Exception => e
            @ui = STDERR unless @ui
            @ui.puts "Error while postmortem console: #{e.inspect}"
          end
        end
      }
    end

    if !@postmortem_hook.enabled?
      @postmortem_hook.enable
    end
  else
    if @postmortem_hook && @postmortem_hook.enabled?
      @postmortem_hook.disable
    end
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 386
    def process_command line
      if line.empty?
        if @repl_prev_line
          line = @repl_prev_line
        else
          return :retry
        end
      else
        @repl_prev_line = line
      end

      /([^\s]+)(?:\s+(.+))?/ =~ line
      cmd, arg = $1, $2

      # p cmd: [cmd, *arg]

      case cmd
      ### Control flow

      # * `s[tep]`
      #   * Step in. Resume the program until next breakable point.
      # * `s[tep] <n>`
      #   * Step in, resume the program at `<n>`th breakable point.
      when 's', 'step'
        cancel_auto_continue
        check_postmortem
        step_command :in, arg

      # * `n[ext]`
      #   * Step over. Resume the program until next line.
      # * `n[ext] <n>`
      #   * Step over, same as `step <n>`.
      when 'n', 'next'
        cancel_auto_continue
        check_postmortem
        step_command :next, arg

      # * `fin[ish]`
      #   * Finish this frame. Resume the program until the current frame is finished.
      # * `fin[ish] <n>`
      #   * Finish `<n>`th frames.
      when 'fin', 'finish'
        cancel_auto_continue
        check_postmortem

        if arg&.to_i == 0
          raise 'finish command with 0 does not make sense.'
        end

        step_command :finish, arg

      # * `c[ontinue]`
      #   * Resume the program.
      when 'c', 'continue'
        cancel_auto_continue
        leave_subsession :continue

      # * `q[uit]` or `Ctrl-D`
      #   * Finish debugger (with the debuggee process on non-remote debugging).
      when 'q', 'quit'
        if ask 'Really quit?'
          @ui.quit arg.to_i
          leave_subsession :continue
        else
          return :retry
        end

      # * `q[uit]!`
      #   * Same as q[uit] but without the confirmation prompt.
      when 'q!', 'quit!'
        @ui.quit arg.to_i
        leave_subsession nil

      # * `kill`
      #   * Stop the debuggee process with `Kernel#exit!`.
      when 'kill'
        if ask 'Really kill?'
          exit! (arg || 1).to_i
        else
          return :retry
        end

      # * `kill!`
      #   * Same as kill but without the confirmation prompt.
      when 'kill!'
        exit! (arg || 1).to_i

      # * `sigint`
      #   * Execute SIGINT handler registered by the debuggee.
      #   * Note that this command should be used just after stop by `SIGINT`.
      when 'sigint'
        begin
          case cmd = @intercepted_sigint_cmd
          when nil, 'IGNORE', :IGNORE, 'DEFAULT', :DEFAULT
            # ignore
          when String
            eval(cmd)
          when Proc
            cmd.call
          end

          leave_subsession :continue

        rescue Exception => e
          @ui.puts "Exception: #{e}"
          @ui.puts e.backtrace.map{|line| "  #{e}"}
          return :retry
        end

      ### Breakpoint

      # * `b[reak]`
      #   * Show all breakpoints.
      # * `b[reak] <line>`
      #   * Set breakpoint on `<line>` at the current frame's file.
      # * `b[reak] <file>:<line>` or `<file> <line>`
      #   * Set breakpoint on `<file>:<line>`.
      # * `b[reak] <class>#<name>`
      #    * Set breakpoint on the method `<class>#<name>`.
      # * `b[reak] <expr>.<name>`
      #    * Set breakpoint on the method `<expr>.<name>`.
      # * `b[reak] ... if: <expr>`
      #   * break if `<expr>` is true at specified location.
      # * `b[reak] ... pre: <command>`
      #   * break and run `<command>` before stopping.
      # * `b[reak] ... do: <command>`
      #   * break and run `<command>`, and continue.
      # * `b[reak] ... path: <path_regexp>`
      #   * break if the triggering event's path matches <path_regexp>.
      # * `b[reak] if: <expr>`
      #   * break if: `<expr>` is true at any lines.
      #   * Note that this feature is super slow.
      when 'b', 'break'
        check_postmortem

        if arg == nil
          show_bps
          return :retry
        else
          case bp = repl_add_breakpoint(arg)
          when :noretry
          when nil
            return :retry
          else
            show_bps bp
            return :retry
          end
        end

      # skip
      when 'bv'
        check_postmortem
        require 'json'

        h = Hash.new{|h, k| h[k] = []}
        @bps.each_value{|bp|
          if LineBreakpoint === bp
            h[bp.path] << {lnum: bp.line}
          end
        }
        if h.empty?
          # TODO: clean?
        else
          open(".rdb_breakpoints.json", 'w'){|f| JSON.dump(h, f)}
        end

        vimsrc = File.join(__dir__, 'bp.vim')
        system("vim -R -S #{vimsrc} #{@tc.location.path}")

        if File.exist?(".rdb_breakpoints.json")
          pp JSON.load(File.read(".rdb_breakpoints.json"))
        end

        return :retry

      # * `catch <Error>`
      #   * Set breakpoint on raising `<Error>`.
      # * `catch ... if: <expr>`
      #   * stops only if `<expr>` is true as well.
      # * `catch ... pre: <command>`
      #   * runs `<command>` before stopping.
      # * `catch ... do: <command>`
      #   * stops and run `<command>`, and continue.
      # * `catch ... path: <path_regexp>`
      #   * stops if the exception is raised from a path that matches <path_regexp>.
      when 'catch'
        check_postmortem

        if arg
          bp = repl_add_catch_breakpoint arg
          show_bps bp if bp
        else
          show_bps
        end
        return :retry

      # * `watch @ivar`
      #   * Stop the execution when the result of current scope's `@ivar` is changed.
      #   * Note that this feature is super slow.
      # * `watch ... if: <expr>`
      #   * stops only if `<expr>` is true as well.
      # * `watch ... pre: <command>`
      #   * runs `<command>` before stopping.
      # * `watch ... do: <command>`
      #   * stops and run `<command>`, and continue.
      # * `watch ... path: <path_regexp>`
      #   * stops if the triggering event's path matches <path_regexp>.
      when 'wat', 'watch'
        check_postmortem

        if arg && arg.match?(/\A@\w+/)
          repl_add_watch_breakpoint(arg)
        else
          show_bps
          return :retry
        end

      # * `del[ete]`
      #   * delete all breakpoints.
      # * `del[ete] <bpnum>`
      #   * delete specified breakpoint.
      when 'del', 'delete'
        check_postmortem

        bp =
        case arg
        when nil
          show_bps
          if ask "Remove all breakpoints?", 'N'
            delete_bp
          end
        when /\d+/
          delete_bp arg.to_i
        else
          nil
        end
        @ui.puts "deleted: \##{bp[0]} #{bp[1]}" if bp
        return :retry

      ### Information

      # * `bt` or `backtrace`
      #   * Show backtrace (frame) information.
      # * `bt <num>` or `backtrace <num>`
      #   * Only shows first `<num>` frames.
      # * `bt /regexp/` or `backtrace /regexp/`
      #   * Only shows frames with method name or location info that matches `/regexp/`.
      # * `bt <num> /regexp/` or `backtrace <num> /regexp/`
      #   * Only shows first `<num>` frames with method name or location info that matches `/regexp/`.
      when 'bt', 'backtrace'
        case arg
        when /\A(\d+)\z/
          @tc << [:show, :backtrace, arg.to_i, nil]
        when /\A\/(.*)\/\z/
          pattern = $1
          @tc << [:show, :backtrace, nil, Regexp.compile(pattern)]
        when /\A(\d+)\s+\/(.*)\/\z/
          max, pattern = $1, $2
          @tc << [:show, :backtrace, max.to_i, Regexp.compile(pattern)]
        else
          @tc << [:show, :backtrace, nil, nil]
        end

      # * `l[ist]`
      #   * Show current frame's source code.
      #   * Next `list` command shows the successor lines.
      # * `l[ist] -`
      #   * Show predecessor lines as opposed to the `list` command.
      # * `l[ist] <start>` or `l[ist] <start>-<end>`
      #   * Show current frame's source code from the line <start> to <end> if given.
      when 'l', 'list'
        case arg ? arg.strip : nil
        when /\A(\d+)\z/
          @tc << [:show, :list, {start_line: arg.to_i - 1}]
        when /\A-\z/
          @tc << [:show, :list, {dir: -1}]
        when /\A(\d+)-(\d+)\z/
          @tc << [:show, :list, {start_line: $1.to_i - 1, end_line: $2.to_i}]
        when nil
          @tc << [:show, :list]
        else
          @ui.puts "Can not handle list argument: #{arg}"
          return :retry
        end

      # * `edit`
      #   * Open the current file on the editor (use `EDITOR` environment variable).
      #   * Note that edited file will not be reloaded.
      # * `edit <file>`
      #   * Open <file> on the editor.
      when 'edit'
        if @ui.remote?
          @ui.puts "not supported on the remote console."
          return :retry
        end

        begin
          arg = resolve_path(arg) if arg
        rescue Errno::ENOENT
          @ui.puts "not found: #{arg}"
          return :retry
        end

        @tc << [:show, :edit, arg]

      # * `i[nfo]`
      #    * Show information about current frame (local/instance variables and defined constants).
      # * `i[nfo] l[ocal[s]]`
      #   * Show information about the current frame (local variables)
      #   * It includes `self` as `%self` and a return value as `%return`.
      # * `i[nfo] i[var[s]]` or `i[nfo] instance`
      #   * Show information about instance variables about `self`.
      # * `i[nfo] c[onst[s]]` or `i[nfo] constant[s]`
      #   * Show information about accessible constants except toplevel constants.
      # * `i[nfo] g[lobal[s]]`
      #   * Show information about global variables
      # * `i[nfo] ... </pattern/>`
      #   * Filter the output with `</pattern/>`.
      # * `i[nfo] th[read[s]]`
      #   * Show all threads (same as `th[read]`).
      when 'i', 'info'
        if /\/(.+)\/\z/ =~ arg
          pat = Regexp.compile($1)
          sub = $~.pre_match.strip
        else
          sub = arg
        end

        case sub
        when nil
          @tc << [:show, :default, pat] # something useful
        when 'l', /^locals?/
          @tc << [:show, :locals, pat]
        when 'i', /^ivars?/i, /^instance[_ ]variables?/i
          @tc << [:show, :ivars, pat]
        when 'c', /^consts?/i, /^constants?/i
          @tc << [:show, :consts, pat]
        when 'g', /^globals?/i, /^global[_ ]variables?/i
          @tc << [:show, :globals, pat]
        when 'th', /threads?/
          thread_list
          return :retry
        else
          @ui.puts "unrecognized argument for info command: #{arg}"
          show_help 'info'
          return :retry
        end

      # * `o[utline]` or `ls`
      #   * Show you available methods, constants, local variables, and instance variables in the current scope.
      # * `o[utline] <expr>` or `ls <expr>`
      #   * Show you available methods and instance variables of the given object.
      #   * If the object is a class/module, it also lists its constants.
      when 'outline', 'o', 'ls'
        @tc << [:show, :outline, arg]

      # * `display`
      #   * Show display setting.
      # * `display <expr>`
      #   * Show the result of `<expr>` at every suspended timing.
      when 'display'
        if arg && !arg.empty?
          @displays << arg
          @tc << [:eval, :try_display, @displays]
        else
          @tc << [:eval, :display, @displays]
        end

      # * `undisplay`
      #   * Remove all display settings.
      # * `undisplay <displaynum>`
      #   * Remove a specified display setting.
      when 'undisplay'
        case arg
        when /(\d+)/
          if @displays[n = $1.to_i]
            @displays.delete_at n
          end
          @tc << [:eval, :display, @displays]
        when nil
          if ask "clear all?", 'N'
            @displays.clear
          end
          return :retry
        end

      ### Frame control

      # * `f[rame]`
      #   * Show the current frame.
      # * `f[rame] <framenum>`
      #   * Specify a current frame. Evaluation are run on specified frame.
      when 'frame', 'f'
        @tc << [:frame, :set, arg]

      # * `up`
      #   * Specify the upper frame.
      when 'up'
        @tc << [:frame, :up]

      # * `down`
      #   * Specify the lower frame.
      when 'down'
        @tc << [:frame, :down]

      ### Evaluate

      # * `p <expr>`
      #   * Evaluate like `p <expr>` on the current frame.
      when 'p'
        @tc << [:eval, :p, arg.to_s]

      # * `pp <expr>`
      #   * Evaluate like `pp <expr>` on the current frame.
      when 'pp'
        @tc << [:eval, :pp, arg.to_s]

      # * `eval <expr>`
      #   * Evaluate `<expr>` on the current frame.
      when 'eval', 'call'
        if arg == nil || arg.empty?
          show_help 'eval'
          @ui.puts "\nTo evaluate the variable `#{cmd}`, use `pp #{cmd}` instead."
          return :retry
        else
          @tc << [:eval, :call, arg]
        end

      # * `irb`
      #   * Invoke `irb` on the current frame.
      when 'irb'
        if @ui.remote?
          @ui.puts "not supported on the remote console."
          return :retry
        end
        @tc << [:eval, :irb]

        # don't repeat irb command
        @repl_prev_line = nil

      ### Trace
      # * `trace`
      #   * Show available tracers list.
      # * `trace line`
      #   * Add a line tracer. It indicates line events.
      # * `trace call`
      #   * Add a call tracer. It indicate call/return events.
      # * `trace exception`
      #   * Add an exception tracer. It indicates raising exceptions.
      # * `trace object <expr>`
      #   * Add an object tracer. It indicates that an object by `<expr>` is passed as a parameter or a receiver on method call.
      # * `trace ... </pattern/>`
      #   * Indicates only matched events to `</pattern/>` (RegExp).
      # * `trace ... into: <file>`
      #   * Save trace information into: `<file>`.
      # * `trace off <num>`
      #   * Disable tracer specified by `<num>` (use `trace` command to check the numbers).
      # * `trace off [line|call|pass]`
      #   * Disable all tracers. If `<type>` is provided, disable specified type tracers.
      when 'trace'
        if (re = /\s+into:\s*(.+)/) =~ arg
          into = $1
          arg.sub!(re, '')
        end

        if (re = /\s\/(.+)\/\z/) =~ arg
          pattern = $1
          arg.sub!(re, '')
        end

        case arg
        when nil
          @ui.puts 'Tracers:'
          @tracers.values.each_with_index{|t, i|
            @ui.puts "* \##{i} #{t}"
          }
          @ui.puts
          return :retry

        when /\Aline\z/
          add_tracer LineTracer.new(@ui, pattern: pattern, into: into)
          return :retry

        when /\Acall\z/
          add_tracer CallTracer.new(@ui, pattern: pattern, into: into)
          return :retry

        when /\Aexception\z/
          add_tracer ExceptionTracer.new(@ui, pattern: pattern, into: into)
          return :retry

        when /\Aobject\s+(.+)/
          @tc << [:trace, :object, $1.strip, {pattern: pattern, into: into}]

        when /\Aoff\s+(\d+)\z/
          if t = @tracers.values[$1.to_i]
            t.disable
            @ui.puts "Disable #{t.to_s}"
          else
            @ui.puts "Unmatched: #{$1}"
          end
          return :retry

        when /\Aoff(\s+(line|call|exception|object))?\z/
          @tracers.values.each{|t|
            if $2.nil? || t.type == $2
              t.disable
              @ui.puts "Disable #{t.to_s}"
            end
          }
          return :retry

        else
          @ui.puts "Unknown trace option: #{arg.inspect}"
          return :retry
        end

      # Record
      # * `record`
      #   * Show recording status.
      # * `record [on|off]`
      #   * Start/Stop recording.
      # * `step back`
      #   * Start replay. Step back with the last execution log.
      #   * `s[tep]` does stepping forward with the last log.
      # * `step reset`
      #   * Stop replay .
      when 'record'
        case arg
        when nil, 'on', 'off'
          @tc << [:record, arg&.to_sym]
        else
          @ui.puts "unknown command: #{arg}"
          return :retry
        end

      ### Thread control

      # * `th[read]`
      #   * Show all threads.
      # * `th[read] <thnum>`
      #   * Switch thread specified by `<thnum>`.
      when 'th', 'thread'
        case arg
        when nil, 'list', 'l'
          thread_list
        when /(\d+)/
          switch_thread $1.to_i
        else
          @ui.puts "unknown thread command: #{arg}"
        end
        return :retry

      ### Configuration
      # * `config`
      #   * Show all configuration with description.
      # * `config <name>`
      #   * Show current configuration of <name>.
      # * `config set <name> <val>` or `config <name> = <val>`
      #   * Set <name> to <val>.
      # * `config append <name> <val>` or `config <name> << <val>`
      #   * Append `<val>` to `<name>` if it is an array.
      # * `config unset <name>`
      #   * Set <name> to default.
      when 'config'
        config_command arg
        return :retry

      # * `source <file>`
      #   * Evaluate lines in `<file>` as debug commands.
      when 'source'
        if arg
          begin
            cmds = File.readlines(path = File.expand_path(arg))
            add_preset_commands path, cmds, kick: true, continue: false
          rescue Errno::ENOENT
            @ui.puts "File not found: #{arg}"
          end
        else
          show_help 'source'
        end
        return :retry

      # * `open`
      #   * open debuggee port on UNIX domain socket and wait for attaching.
      #   * Note that `open` command is EXPERIMENTAL.
      # * `open [<host>:]<port>`
      #   * open debuggee port on TCP/IP with given `[<host>:]<port>` and wait for attaching.
      # * `open vscode`
      #   * open debuggee port for VSCode and launch VSCode if available.
      # * `open chrome`
      #   * open debuggee port for Chrome and wait for attaching.
      when 'open'
        case arg&.downcase
        when '', nil
          repl_open_unix
        when 'vscode'
          repl_open_vscode
        when /\A(.+):(\d+)\z/
          repl_open_tcp $1, $2.to_i
        when /\A(\d+)z/
          repl_open_tcp nil, $1.to_i
        when 'tcp'
          repl_open_tcp CONFIG[:host], (CONFIG[:port] || 0)
        when 'chrome', 'cdp'
          CONFIG[:open_frontend] = 'chrome'
          repl_open_tcp CONFIG[:host], (CONFIG[:port] || 0)
        else
          raise "Unknown arg: #{arg}"
        end

        return :retry

      ### Help

      # * `h[elp]`
      #   * Show help for all commands.
      # * `h[elp] <command>`
      #   * Show help for the given command.
      when 'h', 'help', '?'
        if arg
          show_help arg
        else
          @ui.puts DEBUGGER__.help
        end
        return :retry

      ### END
      else
        @tc << [:eval, :pp, line]
=begin
        @repl_prev_line = nil
        @ui.puts "unknown command: #{line}"
        begin
          require 'did_you_mean'
          spell_checker = DidYouMean::SpellChecker.new(dictionary: DEBUGGER__.commands)
          correction = spell_checker.correct(line.split(/\s/).first || '')
          @ui.puts "Did you mean? #{correction.join(' or ')}" unless correction.empty?
        rescue LoadError
          # Don't use D
        end
        return :retry
=end
      end

    rescue Interrupt
      return :retry
    rescue SystemExit
      raise
    rescue PostmortemError => e
      @ui.puts e.message
      return :retry
    rescue Exception => e
      @ui.puts "[REPL ERROR] #{e.inspect}"
      @ui.puts e.backtrace.map{|e| '  ' + e}
      return :retry
    end

# File debug-1.4.0/lib/debug/session.rb, line 204
def process_event evt
  # variable `@internal_info` is only used for test
  tc, output, ev, @internal_info, *ev_args = evt
  output.each{|str| @ui.puts str} if ev != :suspend

  case ev

  when :thread_begin # special event, tc is nil
    th = ev_args.shift
    q = ev_args.shift
    on_thread_begin th
    q << true

  when :init
    wait_command_loop tc

  when :load
    iseq, src = ev_args
    on_load iseq, src
    @ui.event :load
    tc << :continue

  when :trace
    trace_id, msg = ev_args
    if t = @tracers.values.find{|t| t.object_id == trace_id}
      t.puts msg
    end
    tc << :continue

  when :suspend
    enter_subsession if ev_args.first != :replay
    output.each{|str| @ui.puts str}

    case ev_args.first
    when :breakpoint
      bp, i = bp_index ev_args[1]
      clean_bps unless bp
      @ui.event :suspend_bp, i, bp, tc.id
    when :trap
      @ui.event :suspend_trap, sig = ev_args[1], tc.id

      if sig == :SIGINT && (@intercepted_sigint_cmd.kind_of?(Proc) || @intercepted_sigint_cmd.kind_of?(String))
        @ui.puts "#{@intercepted_sigint_cmd.inspect} is registered as SIGINT handler."
        @ui.puts "`sigint` command execute it."
      end
    else
      @ui.event :suspended, tc.id
    end

    if @displays.empty?
      wait_command_loop tc
    else
      tc << [:eval, :display, @displays]
    end

  when :result
    raise "[BUG] not in subsession" unless @subsession

    case ev_args.first
    when :try_display
      failed_results = ev_args[1]
      if failed_results.size > 0
        i, _msg = failed_results.last
        if i+1 == @displays.size
          @ui.puts "canceled: #{@displays.pop}"
        end
      end

    when :method_breakpoint, :watch_breakpoint
      bp = ev_args[1]
      if bp
        add_bp(bp)
        show_bps bp
      else
        # can't make a bp
      end
    when :trace_pass
      obj_id = ev_args[1]
      obj_inspect = ev_args[2]
      opt = ev_args[3]
      add_tracer ObjectTracer.new(@ui, obj_id, obj_inspect, **opt)
    else
      # ignore
    end

    wait_command_loop tc

  when :dap_result
    dap_event ev_args # server.rb
    wait_command_loop tc
  when :cdp_result
    cdp_event ev_args
    wait_command_loop tc
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1705
def process_info
  if @process_group.multi?
    "#{$0}\##{Process.pid}"
  end
end

# File debug-1.4.0/lib/debug/server_cdp.rb, line 521
def process_protocol_request req
  case req['method']
  when 'Debugger.stepOver', 'Debugger.stepInto', 'Debugger.stepOut', 'Debugger.resume', 'Debugger.getScriptSource'
    @tc << [:cdp, :backtrace, req]
  when 'Debugger.evaluateOnCallFrame'
    frame_id = req.dig('params', 'callFrameId')
    if fid = @frame_map[frame_id]
      expr = req.dig('params', 'expression')
      @tc << [:cdp, :evaluate, req, fid, expr]
    else
      fail_response req,
                    code: INVALID_PARAMS,
                    message: "'callFrameId' is an invalid"
    end
  when 'Runtime.getProperties'
    oid = req.dig('params', 'objectId')
    if ref = @obj_map[oid]
      case ref[0]
      when 'local'
        frame_id = ref[1]
        fid = @frame_map[frame_id]
        @tc << [:cdp, :scope, req, fid]
      when 'properties'
        @tc << [:cdp, :properties, req, oid]
      when 'script', 'global'
        # TODO: Support script and global types
        @ui.respond req
        return :retry
      else
        raise "Unknown type: #{ref.inspect}"
      end
    else
      fail_response req,
                    code: INVALID_PARAMS,
                    message: "'objectId' is an invalid"
    end
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 345
def prompt
  if @postmortem
    '(rdbg:postmortem) '
  elsif @process_group.multi?
    "(rdbg@#{process_info}) "
  else
    '(rdbg) '
  end
end

# File debug-1.4.0/lib/debug/server_dap.rb, line 571
def register_var v, tid
  if (tl_vid = v[:variablesReference]) > 0
    vid = @var_map.size + 1
    @var_map[vid] = [:variable, tid, tl_vid]
    v[:variablesReference] = vid
  end
end

# File debug-1.4.0/lib/debug/server_dap.rb, line 579
def register_vars vars, tid
  raise tid.inspect unless tid.kind_of?(Integer)
  vars.each{|v|
    register_var v, tid
  }
end

# File debug-1.4.0/lib/debug/session.rb, line 1218
def rehash_bps
  bps = @bps.values
  @bps.clear
  bps.each{|bp|
    add_bp bp
  }
end

# File debug-1.4.0/lib/debug/session.rb, line 1278
def repl_add_breakpoint arg
  expr = parse_break arg.strip
  cond = expr[:if]
  cmd = ['break', expr[:pre], expr[:do]] if expr[:pre] || expr[:do]
  path = Regexp.compile(expr[:path]) if expr[:path]

  case expr[:sig]
  when /\A(\d+)\z/
    add_line_breakpoint @tc.location.path, $1.to_i, cond: cond, command: cmd
  when /\A(.+)[:\s+](\d+)\z/
    add_line_breakpoint $1, $2.to_i, cond: cond, command: cmd
  when /\A(.+)([\.\#])(.+)\z/
    @tc << [:breakpoint, :method, $1, $2, $3, cond, cmd, path]
    return :noretry
  when nil
    add_check_breakpoint cond, path
  else
    @ui.puts "Unknown breakpoint format: #{arg}"
    @ui.puts
    show_help 'b'
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1301
def repl_add_catch_breakpoint arg
  expr = parse_break arg.strip
  cond = expr[:if]
  cmd = ['catch', expr[:pre], expr[:do]] if expr[:pre] || expr[:do]
  path = Regexp.compile(expr[:path]) if expr[:path]

  bp = CatchBreakpoint.new(expr[:sig], cond: cond, command: cmd, path: path)
  add_bp bp
end

# File debug-1.4.0/lib/debug/session.rb, line 1311
def repl_add_watch_breakpoint arg
  expr = parse_break arg.strip
  cond = expr[:if]
  cmd = ['watch', expr[:pre], expr[:do]] if expr[:pre] || expr[:do]
  path = Regexp.compile(expr[:path]) if expr[:path]

  @tc << [:breakpoint, :watch, expr[:sig], cond, cmd, path]
end

# File debug-1.4.0/lib/debug/session.rb, line 1044
def repl_open_setup
  @tp_thread_begin.disable
  @ui.activate self
  if @ui.respond_to?(:reader_thread) && thc = get_thread_client(@ui.reader_thread)
    thc.mark_as_management
  end
  @tp_thread_begin.enable
end

# File debug-1.4.0/lib/debug/session.rb, line 1053
def repl_open_tcp host, port, **kw
  DEBUGGER__.open_tcp host: host, port: port, nonstop: true, **kw
  repl_open_setup
end

# File debug-1.4.0/lib/debug/session.rb, line 1058
def repl_open_unix
  DEBUGGER__.open_unix nonstop: true
  repl_open_setup
end

# File debug-1.4.0/lib/debug/session.rb, line 1063
def repl_open_vscode
  CONFIG[:open_frontend] = 'vscode'
  repl_open_unix
end

# File debug-1.4.0/lib/debug/session.rb, line 187
def reset_ui ui
  @ui.deactivate
  @ui = ui
end

# File debug-1.4.0/lib/debug/session.rb, line 1546
def resolve_path file
  File.realpath(File.expand_path(file))
rescue Errno::ENOENT
  case file
  when '-e', '-'
    return file
  else
    $LOAD_PATH.each do |lp|
      libpath = File.join(lp, file)
      return File.realpath(libpath)
    rescue Errno::ENOENT
      # next
    end
  end

  raise
end

# File debug-1.4.0/lib/debug/session.rb, line 1677
def save_int_trap cmd
  prev, @intercepted_sigint_cmd = @intercepted_sigint_cmd, cmd
  prev
end

# File debug-1.4.0/lib/debug/session.rb, line 196
def session_server_main
  while evt = pop_event
    process_event evt
  end
ensure
  deactivate
end

# File debug-1.4.0/lib/debug/session.rb, line 1410
def setup_threads
  prev_clients = @th_clients
  @th_clients = {}

  Thread.list.each{|th|
    if tc = prev_clients[th]
      @th_clients[th] = tc
    else
      create_thread_client(th)
    end
  }
end

# File debug-1.4.0/lib/debug/session.rb, line 1203
def show_bps specific_bp = nil
  iterate_bps do |key, bp, i|
    @ui.puts "#%d %s" % [i, bp.to_s] if !specific_bp || bp == specific_bp
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1162
def show_help arg
  DEBUGGER__.helps.each{|cat, cs|
    cs.each{|ws, desc|
      if ws.include? arg
        @ui.puts desc
        return
      end
    }
  }
  @ui.puts "not found: #{arg}"
end

# File debug-1.4.0/lib/debug/session.rb, line 317
def source iseq
  if !CONFIG[:no_color]
    @sr.get_colored(iseq)
  else
    @sr.get(iseq)
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1068
def step_command type, arg
  case arg
  when nil, /\A\d+\z/
    if type == :in && @tc.recorder&.replaying?
      @tc << [:step, type, arg&.to_i]
    else
      leave_subsession [:step, type, arg&.to_i]
    end
  when /\Aback\z/, /\Areset\z/
    if type != :in
      @ui.puts "only `step #{arg}` is supported."
      :retry
    else
      @tc << [:step, arg.to_sym]
    end
  else
    @ui.puts "Unknown option: #{arg}"
    :retry
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1397
def switch_thread n
  thcs, _unmanaged_ths = update_thread_list

  if tc = thcs[n]
    if tc.waiting?
      @tc = tc
    else
      @ui.puts "#{tc.thread} is not controllable yet."
    end
  end
  thread_list
end

# File debug-1.4.0/lib/debug/session.rb, line 1378
def thread_list
  thcs, unmanaged_ths = update_thread_list
  thcs.each_with_index{|thc, i|
    @ui.puts "#{@tc == thc ? "--> " : "    "}\##{i} #{thc}"
  }

  if !unmanaged_ths.empty?
    @ui.puts "The following threads are not managed yet by the debugger:"
    unmanaged_ths.each{|th|
      @ui.puts "     " + th.to_s
    }
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1360
def update_thread_list
  list = Thread.list
  thcs = []
  unmanaged = []

  list.each{|th|
    if thc = @th_clients[th]
      if !thc.management?
        thcs << thc
      end
    else
      unmanaged << th
    end
  }

  return thcs.sort_by{|thc| thc.id}, unmanaged
end

# File debug-1.4.0/lib/debug/session.rb, line 355
def wait_command
  if @preset_command
    if @preset_command.commands.empty?
      if @preset_command.auto_continue
        @preset_command = nil

        leave_subsession :continue
        return
      else
        @preset_command = nil
        return :retry
      end
    else
      line = @preset_command.commands.shift
      @ui.puts "(rdbg:#{@preset_command.source}) #{line}"
    end
  else
    @ui.puts "INTERNAL_INFO: #{JSON.generate(@internal_info)}" if ENV['RUBY_DEBUG_TEST_MODE']
    line = @ui.readline prompt
  end

  case line
  when String
    process_command line
  when Hash
    process_protocol_request line # defined in server.rb
  else
    raise "unexpected input: #{line.inspect}"
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 329
def wait_command_loop tc
  @tc = tc

  loop do
    case wait_command
    when :retry
      # nothing
    else
      break
    end
  rescue Interrupt
    @ui.puts "\n^C"
    retry
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1588
def width
  @ui.width
end

# File debug-1.4.0/lib/debug/session.rb, line 1437
        def ask_thread_client th
  # TODO: Ractor support
  q2 = Queue.new
  # tc, output, ev, @internal_info, *ev_args = evt
  @q_evt << [nil, [], :thread_begin, nil, th, q2]
  q2.pop

  @th_clients[th] or raise "unexpected error"
end

# File debug-1.4.0/lib/debug/session.rb, line 1431
        def create_thread_client th
  # TODO: Ractor support
  raise "Only session_server can create thread_client" unless Thread.current == @session_server
  @th_clients[th] = ThreadClient.new((@tc_id += 1), @q_evt, Queue.new, th)
end

# File debug-1.4.0/lib/debug/session.rb, line 1505
        def enter_subsession
  raise "already in subsession" if @subsession
  @subsession = true
  stop_all_threads
  @process_group.lock
  DEBUGGER__.info "enter_subsession"
end

# File debug-1.4.0/lib/debug/session.rb, line 1513
        def leave_subsession type
  DEBUGGER__.info "leave_subsession"
  @process_group.unlock
  restart_all_threads
  @tc << type if type
  @tc = nil
  @subsession = false
rescue Exception => e
  STDERR.puts [e, e.backtrace].inspect
  raise
end

# File debug-1.4.0/lib/debug/session.rb, line 1495
        def restart_all_threads
  stopper = @thread_stopper
  stopper.disable if stopper.enabled?

  waiting_thread_clients.each{|tc|
    next if @tc == tc
    tc << :continue
  }
end

# File debug-1.4.0/lib/debug/session.rb, line 1460
        def running_thread_clients_count
  @th_clients.count{|th, tc|
    next if tc.management?
    next unless tc.running?
    true
  }
end

# File debug-1.4.0/lib/debug/session.rb, line 1488
        def stop_all_threads
  return if running_thread_clients_count == 0

  stopper = @thread_stopper
  stopper.enable unless stopper.enabled?
end

# File debug-1.4.0/lib/debug/session.rb, line 1476
        def thread_stopper
  TracePoint.new(:line) do
    # run on each thread
    tc = ThreadClient.current
    next if tc.management?
    next unless tc.running?
    next if tc == @tc

    tc.on_pause
  end
end

# File debug-1.4.0/lib/debug/session.rb, line 1468
        def waiting_thread_clients
  @th_clients.map{|th, tc|
    next if tc.management?
    next unless tc.waiting?
    tc
  }.compact
end