Module: Dexc

Defined in:
lib/dexc.rb,
lib/dexc/version.rb

Defined Under Namespace

Modules: IrbHelper Classes: RaiseEvent, ReturnEvent, RingBuffer

Constant Summary collapse

EXC_CALLERS_VAR = 
:@dexc_callers
VERSION = 
"0.1.0"

Class Method Summary collapse

Class Method Details

.show_line(path, lineno, index, index_width, cache) ⇒ Object 



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# File 'lib/dexc.rb', line 152

def show_line(path, lineno, index, index_width, cache)
  print "#{"%#{index_width}d" % index}:#{path}:#{lineno}"
  begin
    cache[path] ||= open(path).each_line.map(&:chomp)
    print "> #{lineno > 0 ? ::IRB::Color.colorize_code(cache[path][lineno - 1], complete: false, ignore_error: true) : ''}"
  rescue Errno::ENOENT
    cache[path] = []
  end
  puts
end

.show_trace(events) ⇒ Object 



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# File 'lib/dexc.rb', line 141

def show_trace(events)
  idx_width = (events.length - 1).to_s.length
  file_cache = {}
  events.each_with_index do |i, idx|
    show_line(i.path, i.lineno, idx, idx_width, file_cache)
    puts " " * (idx_width + 1) + "#{i.defined_class}##{i.method_id}#{i.event == :b_return ? '(block)' : ''}: #{IRB::ColorPrinter.pp(i.return_value.inspect, '')}"
  end
  puts
end

.start ⇒ Object 



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# File 'lib/dexc.rb', line 75

def start
  events = RingBuffer.new(30)

  tp = TracePoint.new(:raise, :return, :c_return, :b_return) do |tp|
    if tp.event == :raise
      exc = tp.raised_exception
      exc.instance_variable_set(EXC_CALLERS_VAR, tp.binding.callers[1..-1])
      events.add(RaiseEvent.new(tp.event, exc))
    else
      events.add(ReturnEvent.new(tp.event, tp.lineno, tp.path, tp.defined_class, tp.method_id, tp.return_value))
    end
  end

  at_exit do
    exc = $!
    tp.disable
    callers = exc.instance_variable_get(EXC_CALLERS_VAR)
    if exc.kind_of?(StandardError) and callers
      raise_idx = events.to_a.find_index {|i| i.event == :raise and i.raised_exception == exc }
      latest_events = raise_idx ? events.to_a[0...raise_idx] : []
      return_events = latest_events.find_all {|i| i.event != :raise }
      return_values = return_events.map(&:return_value)

      show_trace(return_events)
      puts exc.full_message

      Kernel.module_eval do
        define_method(:dexc_hist) do
          return_values
        end
        alias_method :hist, :dexc_hist
      end

      begin
        require 'pry'
        Pry.config.hooks.add_hook(:when_started, :dexc_init_ex) do |_, _, pry|
          pry.last_exception = exc
          pry.backtrace = (exc.backtrace || [])
        end
        callers[0].pry
      rescue LoadError
        require 'irb'
        IRB::Context.include(IrbHelper)
        require 'dexc/irb/cmd/stack_explorer'
        b = callers[0]
        filename = b.source_location[0]
        IRB.setup(filename, argv: [])
        workspace = IRB::WorkSpace.new(b)
        STDOUT.print(workspace.code_around_binding)
        binding_irb = IRB::Irb.new(workspace)
        binding_irb.context.irb_path = File.expand_path(filename)
        binding_irb.context.instance_eval do
          @dexc_callers = callers
          @dexc_callers_width = Math.log10(callers.length).floor + 1
          @dexc_callers_idx = 0
        end
        binding_irb.run(IRB.conf)
      end
      exit!
    end
  end

  tp.enable
end