debug.rb

# Copyright (C) 2000  Network Applied Communication Laboratory, Inc.
# Copyright (C) 2000  Information-technology Promotion Agency, Japan

if $SAFE > 0
  STDERR.print "-r debug.rb is not available in safe mode\n"
  exit 1
end

require 'tracer'
require 'pp'

class Tracer
  def Tracer.trace_func(*vars)
    Single.trace_func(*vars)
  end
end

SCRIPT_LINES__ = {} unless defined? SCRIPT_LINES__

class DEBUGGER__
class Mutex
  def initialize
    @locker = nil
    @waiting = []
    @locked = false;
  end

  def locked?
    @locked
  end

  def lock
    return if @locker == Thread.current
    while (Thread.critical = true; @locked)
      @waiting.push Thread.current
      Thread.stop
    end
    @locked = true
    @locker = Thread.current
    Thread.critical = false
    self
  end

  def unlock
    return unless @locked
    unless @locker == Thread.current
      raise RuntimeError, "unlocked by other"
    end
    Thread.critical = true
    t = @waiting.shift
    @locked = false
    @locker = nil
    Thread.critical = false
    t.run if t
    self
  end
end
MUTEX = Mutex.new

class Context
  DEBUG_LAST_CMD = []

  begin
    require 'readline'
    def readline(prompt, hist)
      Readline::readline(prompt, hist)
    end
  rescue LoadError
    def readline(prompt, hist)
      STDOUT.print prompt
      STDOUT.flush
      line = STDIN.gets
      exit unless line
      line.chomp!
      line
    end
    USE_READLINE = false
  end

  def initialize
    if Thread.current == Thread.main
      @stop_next = 1
    else
      @stop_next = 0
    end
    @last_file = nil
    @file = nil
    @line = nil
    @no_step = nil
    @frames = []
    @finish_pos = 0
    @trace = false
    @catch = "StandardError"
    @suspend_next = false
  end

  def stop_next(n=1)
    @stop_next = n
  end

  def set_suspend
    @suspend_next = true
  end

  def clear_suspend
    @suspend_next = false
  end

  def suspend_all
    DEBUGGER__.suspend
  end

  def resume_all
    DEBUGGER__.resume
  end

  def check_suspend
    while (Thread.critical = true; @suspend_next)
      DEBUGGER__.waiting.push Thread.current
      @suspend_next = false
      Thread.stop
    end
    Thread.critical = false
  end

  def trace?
    @trace
  end

  def set_trace(arg)
    @trace = arg
  end

  def stdout
    DEBUGGER__.stdout
  end

  def break_points
    DEBUGGER__.break_points
  end

  def display
    DEBUGGER__.display
  end

  def context(th)
    DEBUGGER__.context(th)
  end

  def set_trace_all(arg)
    DEBUGGER__.set_trace(arg)
  end

  def set_last_thread(th)
    DEBUGGER__.set_last_thread(th)
  end

  def debug_eval(str, binding)
    begin
      val = eval(str, binding)
      val
    rescue StandardError, ScriptError
      at = eval("caller(0)", binding)
      stdout.printf "%s:%s\n", at.shift, $!.to_s.sub(/\(eval\):1:(in `.*?':)?/, '') #`
      for i in at
	stdout.printf "\tfrom %s\n", i
      end
      throw :debug_error
    end
  end

  def debug_silent_eval(str, binding)
    begin
      val = eval(str, binding)
      val
    rescue StandardError, ScriptError
      nil
    end
  end

  def var_list(ary, binding)
    ary.sort!
    for v in ary
      stdout.printf "  %s => %s\n", v, eval(v, binding).inspect
    end
  end

  def debug_variable_info(input, binding)
    case input
    when /^\s*g(?:lobal)?$/
      var_list(global_variables, binding)

    when /^\s*l(?:ocal)?$/
      var_list(eval("local_variables", binding), binding)

    when /^\s*i(?:nstance)?\s+/
      obj = debug_eval($', binding)
      var_list(obj.instance_variables, obj.instance_eval{binding()})

    when /^\s*c(?:onst(?:ant)?)?\s+/
      obj = debug_eval($', binding)
      unless obj.kind_of? Module
	stdout.print "Should be Class/Module: ", $', "\n"
      else
	var_list(obj.constants, obj.module_eval{binding()})
      end
    end
  end

  def debug_method_info(input, binding)
    case input
    when /^i(:?nstance)?\s+/
      obj = debug_eval($', binding)

      len = 0
      for v in obj.methods.sort
	len += v.size + 1
	if len > 70
	  len = v.size + 1
	  stdout.print "\n"
	end
	stdout.print v, " "
      end
      stdout.print "\n"

    else
      obj = debug_eval(input, binding)
      unless obj.kind_of? Module
	stdout.print "Should be Class/Module: ", input, "\n"
      else
	len = 0
	for v in obj.instance_methods.sort
	  len += v.size + 1
	  if len > 70
	    len = v.size + 1
	    stdout.print "\n"
	  end
	  stdout.print v, " "
	end
	stdout.print "\n"
      end
    end
  end

  def thnum
    num = DEBUGGER__.instance_eval{@thread_list[Thread.current]}
    unless num
      DEBUGGER__.make_thread_list
      num = DEBUGGER__.instance_eval{@thread_list[Thread.current]}
    end
    num
  end

  def debug_command(file, line, id, binding)
    MUTEX.lock
    set_last_thread(Thread.current)
    frame_pos = 0
    binding_file = file
    binding_line = line
    previous_line = nil
    if (ENV['EMACS'] == 't')
      stdout.printf "\032\032%s:%d:\n", binding_file, binding_line
    else
      stdout.printf "%s:%d:%s", binding_file, binding_line,
	line_at(binding_file, binding_line)
    end
    @frames[0] = [binding, file, line, id]
    display_expressions(binding)
    prompt = true
    while prompt and input = readline("(rdb:%d) "%thnum(), true)
      catch(:debug_error) do
	if input == ""
	  input = DEBUG_LAST_CMD[0]
	  stdout.print input, "\n"
	else
	  DEBUG_LAST_CMD[0] = input
	end

	case input
	when /^\s*tr(?:ace)?(?:\s+(on|off))?(?:\s+(all))?$/
          if defined?( $2 )
            if $1 == 'on'
              set_trace_all true
            else
              set_trace_all false
            end
          elsif defined?( $1 )
            if $1 == 'on'
              set_trace true
            else
              set_trace false
            end
          end
          if trace?
            stdout.print "Trace on.\n"
          else
            stdout.print "Trace off.\n"
          end

	when /^\s*b(?:reak)?\s+(?:(.+):)?(.+)$/
	  pos = $2
	  file = File.basename($1) if $1
	  if pos =~ /^\d+$/
	    pname = pos
	    pos = pos.to_i
	  else
	    pname = pos = pos.intern.id2name
	  end
	  break_points.push [true, 0, file, pos]
	  stdout.printf "Set breakpoint %d at %s:%s\n", break_points.size, file, pname

	when /^\s*wat(?:ch)?\s+(.+)$/
	  exp = $1
	  break_points.push [true, 1, exp]
	  stdout.printf "Set watchpoint %d\n", break_points.size, exp

	when /^\s*b(?:reak)?$/
	  if break_points.find{|b| b[1] == 0}
	    n = 1
	    stdout.print "Breakpoints:\n"
	    for b in break_points
	      if b[0] and b[1] == 0
		stdout.printf "  %d %s:%s\n", n, b[2], b[3] 
	      end
	      n += 1
	    end
	  end
	  if break_points.find{|b| b[1] == 1}
	    n = 1
	    stdout.print "\n"
	    stdout.print "Watchpoints:\n"
	    for b in break_points
	      if b[0] and b[1] == 1
		stdout.printf "  %d %s\n", n, b[2]
	      end
	      n += 1
	    end
	  end
	  if break_points.size == 0
	    stdout.print "No breakpoints\n"
	  else
	    stdout.print "\n"
	  end

	when /^\s*del(?:ete)?(?:\s+(\d+))?$/
	  pos = $1
	  unless pos
	    input = readline("Clear all breakpoints? (y/n) ", false)
	    if input == "y"
	      for b in break_points
		b[0] = false
	      end
	    end
	  else
	    pos = pos.to_i
	    if break_points[pos-1]
	      break_points[pos-1][0] = false
	    else
	      stdout.printf "Breakpoint %d is not defined\n", pos
	    end
	  end

	when /^\s*disp(?:lay)?\s+(.+)$/
	  exp = $1
	  display.push [true, exp]
	  stdout.printf "%d: ", display.size
	  display_expression(exp, binding)

	when /^\s*disp(?:lay)?$/
	  display_expressions(binding)

	when /^\s*undisp(?:lay)?(?:\s+(\d+))?$/
	  pos = $1
	  unless pos
	    input = readline("Clear all expressions? (y/n) ", false)
	    if input == "y"
	      for d in display
		d[0] = false
	      end
	    end
	  else
	    pos = pos.to_i
	    if display[pos-1]
	      display[pos-1][0] = false
	    else
	      stdout.printf "Display expression %d is not defined\n", pos
	    end
	  end

	when /^\s*c(?:ont)?$/
	  prompt = false

	when /^\s*s(?:tep)?(?:\s+(\d+))?$/
	  if $1
	    lev = $1.to_i
	  else
	    lev = 1
	  end
	  @stop_next = lev
	  prompt = false

	when /^\s*n(?:ext)?(?:\s+(\d+))?$/
	  if $1
	    lev = $1.to_i
	  else
	    lev = 1
	  end
	  @stop_next = lev
	  @no_step = @frames.size - frame_pos
	  prompt = false

	when /^\s*w(?:here)?$/, /^\s*f(?:rame)?$/
	  display_frames(frame_pos)

	when /^\s*l(?:ist)?(?:\s+(.+))?$/
	  if not $1
	    b = previous_line ? previous_line + 10 : binding_line - 5
	    e = b + 9
	  elsif $1 == '-'
	    b = previous_line ? previous_line - 10 : binding_line - 5
	    e = b + 9
	  else
	    b, e = $1.split(/[-,]/)
	    if e
	      b = b.to_i
	      e = e.to_i
	    else
	      b = b.to_i - 5
	      e = b + 9
	    end
	  end
	  previous_line = b
	  display_list(b, e, binding_file, binding_line)

	when /^\s*up(?:\s+(\d+))?$/
	  previous_line = nil
	  if $1
	    lev = $1.to_i
	  else
	    lev = 1
	  end
	  frame_pos += lev
	  if frame_pos >= @frames.size
	    frame_pos = @frames.size - 1
	    stdout.print "At toplevel\n"
	  end
	  binding, binding_file, binding_line = @frames[frame_pos]
	  stdout.print format_frame(frame_pos)

	when /^\s*down(?:\s+(\d+))?$/
	  previous_line = nil
	  if $1
	    lev = $1.to_i
	  else
	    lev = 1
	  end
	  frame_pos -= lev
	  if frame_pos < 0
	    frame_pos = 0
	    stdout.print "At stack bottom\n"
	  end
	  binding, binding_file, binding_line = @frames[frame_pos]
	  stdout.print format_frame(frame_pos)

	when /^\s*fin(?:ish)?$/
	  if frame_pos == @frames.size
	    stdout.print "\"finish\" not meaningful in the outermost frame.\n"
	  else
	    @finish_pos = @frames.size - frame_pos
	    frame_pos = 0
	    prompt = false
	  end

	when /^\s*cat(?:ch)?(?:\s+(.+))?$/
	  if $1
	    excn = $1
	    if excn == 'off'
	      @catch = nil
	      stdout.print "Clear catchpoint.\n"
	    else
	      @catch = excn
	      stdout.printf "Set catchpoint %s.\n", @catch
	    end
	  else
	    if @catch
	      stdout.printf "Catchpoint %s.\n", @catch
	    else
	      stdout.print "No catchpoint.\n"
	    end
	  end

	when /^\s*q(?:uit)?$/
	  input = readline("Really quit? (y/n) ", false)
	  if input == "y"
	    exit!	# exit -> exit!: No graceful way to stop threads...
	  end

	when /^\s*v(?:ar)?\s+/
	  debug_variable_info($', binding)

	when /^\s*m(?:ethod)?\s+/
	  debug_method_info($', binding)

	when /^\s*th(?:read)?\s+/
	  if DEBUGGER__.debug_thread_info($', binding) == :cont
	    prompt = false
	  end

	when /^\s*pp\s+/
	  PP.pp(debug_eval($', binding), stdout)

	when /^\s*p\s+/
	  stdout.printf "%s\n", debug_eval($', binding).inspect

	when /^\s*h(?:elp)?$/
	  debug_print_help()

	else
	  v = debug_eval(input, binding)
	  stdout.printf "%s\n", v.inspect unless (v == nil)
	end
      end
    end
    MUTEX.unlock
    resume_all
  end

  def debug_print_help
    stdout.print <<EOHELP
Debugger help v.-0.002b
Commands
  b[reak] [file|method:]<line|method>
                             set breakpoint to some position
  wat[ch] <expression>       set watchpoint to some expression
  cat[ch] <an Exception>     set catchpoint to an exception
  b[reak]                    list breakpoints
  cat[ch]                    show catchpoint
  del[ete][ nnn]             delete some or all breakpoints
  disp[lay] <expression>     add expression into display expression list
  undisp[lay][ nnn]          delete one particular or all display expressions
  c[ont]                     run until program ends or hit breakpoint
  s[tep][ nnn]               step (into methods) one line or till line nnn
  n[ext][ nnn]               go over one line or till line nnn
  w[here]                    display frames
  f[rame]                    alias for where
  l[ist][ (-|nn-mm)]         list program, - lists backwards
                             nn-mm lists given lines
  up[ nn]                    move to higher frame
  down[ nn]                  move to lower frame
  fin[ish]                   return to outer frame
  tr[ace] (on|off)           set trace mode of current thread
  tr[ace] (on|off) all       set trace mode of all threads
  q[uit]                     exit from debugger
  v[ar] g[lobal]             show global variables
  v[ar] l[ocal]              show local variables
  v[ar] i[nstance] <object>  show instance variables of object
  v[ar] c[onst] <object>     show constants of object
  m[ethod] i[nstance] <obj>  show methods of object
  m[ethod] <class|module>    show instance methods of class or module
  th[read] l[ist]            list all threads
  th[read] c[ur[rent]]       show current thread
  th[read] [sw[itch]] <nnn>  switch thread context to nnn
  th[read] stop <nnn>        stop thread nnn
  th[read] resume <nnn>      resume thread nnn
  p expression               evaluate expression and print its value
  h[elp]                     print this help
  <everything else>          evaluate
EOHELP
  end

  def display_expressions(binding)
    n = 1
    for d in display
      if d[0]
	stdout.printf "%d: ", n
	display_expression(d[1], binding)
      end
      n += 1
    end
  end

  def display_expression(exp, binding)
    stdout.printf "%s = %s\n", exp, debug_silent_eval(exp, binding).to_s
  end

  def frame_set_pos(file, line)
    if @frames[0]
      @frames[0][1] = file
      @frames[0][2] = line
    end
  end

  def display_frames(pos)
    0.upto(@frames.size - 1) do |n|
      if n == pos
	stdout.print "--> "
      else
	stdout.print "    "
      end
      stdout.print format_frame(n)
    end
  end

  def format_frame(pos)
    bind, file, line, id = @frames[pos]
    sprintf "#%d %s:%s%s\n", pos + 1, file, line,
      (id ? ":in `#{id.id2name}'" : "")
  end

  def display_list(b, e, file, line)
    stdout.printf "[%d, %d] in %s\n", b, e, file
    if lines = SCRIPT_LINES__[file] and lines != true
      n = 0
      b.upto(e) do |n|
	if n > 0 && lines[n-1]
	  if n == line
	    stdout.printf "=> %d  %s\n", n, lines[n-1].chomp
	  else
	    stdout.printf "   %d  %s\n", n, lines[n-1].chomp
	  end
	end
      end
    else
      stdout.printf "No sourcefile available for %s\n", file
    end
  end

  def line_at(file, line)
    lines = SCRIPT_LINES__[file]
    if lines
      return "\n" if lines == true
      line = lines[line-1]
      return "\n" unless line
      return line
    end
    return "\n"
  end

  def debug_funcname(id)
    if id.nil?
      "toplevel"
    else
      id.id2name
    end
  end

  def check_break_points(file, pos, binding, id)
    return false if break_points.empty?
    file = File.basename(file)
    n = 1
    for b in break_points
      if b[0]
	if b[1] == 0 and b[2] == file and b[3] == pos
	  stdout.printf "Breakpoint %d, %s at %s:%s\n", n, debug_funcname(id), file, pos
	  return true
	elsif b[1] == 1
	  if debug_silent_eval(b[2], binding)
	    stdout.printf "Watchpoint %d, %s at %s:%s\n", n, debug_funcname(id), file, pos
	    return true
	  end
	end
      end
      n += 1
    end
    return false
  end

  def excn_handle(file, line, id, binding)
    stdout.printf "%s:%d: `%s' (%s)\n", file, line, $!, $!.type
    if $!.type <= SystemExit
      set_trace_func nil
      exit
    end

    if @catch and ($!.type.ancestors.find { |e| e.to_s == @catch })
      fs = @frames.size
      tb = caller(0)[-fs..-1]
      if tb
	for i in tb
	  stdout.printf "\tfrom %s\n", i
	end
      end
      suspend_all
      debug_command(file, line, id, binding)
    end
  end

  def trace_func(event, file, line, id, binding, klass)
    Tracer.trace_func(event, file, line, id, binding, klass) if trace?
    context(Thread.current).check_suspend
    @file = file
    @line = line
    case event
    when 'line'
      frame_set_pos(file, line)
      if !@no_step or @frames.size == @no_step
	@stop_next -= 1
      elsif @frames.size < @no_step
	@stop_next = 0		# break here before leaving...
      else
	# nothing to do. skipped.
      end
      if @stop_next == 0 or check_break_points(file, line, binding, id)
	@no_step = nil
	suspend_all
	debug_command(file, line, id, binding)
      end

    when 'call'
      @frames.unshift [binding, file, line, id]
      if check_break_points(file, id.id2name, binding, id) or
	  check_break_points(klass.to_s, id.id2name, binding, id)
	suspend_all
	debug_command(file, line, id, binding)
      end

    when 'c-call'
      frame_set_pos(file, line)

    when 'class'
      @frames.unshift [binding, file, line, id]

    when 'return', 'end'
      if @frames.size == @finish_pos
	@stop_next = 1
	@finish_pos = 0
      end
      @frames.shift

    when 'end'
      @frames.shift

    when 'raise' 
      excn_handle(file, line, id, binding)

    end
    @last_file = file
  end
end

trap("INT") { DEBUGGER__.interrupt }
@last_thread = Thread::main
@max_thread = 1
@thread_list = {Thread::main => 1}
@break_points = []
@display = []
@waiting = []
@stdout = STDOUT

class << DEBUGGER__
  def stdout
    @stdout
  end

  def stdout=(s)
    @stdout = s
  end

  def display
    @display
  end

  def break_points
    @break_points
  end

  def waiting
    @waiting
  end

  def set_trace( arg )
    Thread.critical = true
    make_thread_list
    for th in @thread_list
      context(th[0]).set_trace arg
    end
    Thread.critical = false
    arg
  end

  def set_last_thread(th)
    @last_thread = th
  end

  def suspend
    Thread.critical = true
    make_thread_list
    for th in @thread_list
      next if th[0] == Thread.current
      context(th[0]).set_suspend
    end
    Thread.critical = false
    # Schedule other threads to suspend as soon as possible.
    Thread.pass
  end

  def resume
    Thread.critical = true
    make_thread_list
    for th in @thread_list
      next if th[0] == Thread.current
      context(th[0]).clear_suspend
    end
    waiting.each do |th|
      th.run
    end
    waiting.clear
    Thread.critical = false
    # Schedule other threads to restart as soon as possible.
    Thread.pass
  end

  def context(thread=Thread.current)
    c = thread[:__debugger_data__]
    unless c
      thread[:__debugger_data__] = c = Context.new
    end
    c
  end

  def interrupt
    context(@last_thread).stop_next
  end

  def get_thread(num)
    th = @thread_list.index(num)
    unless th
      @stdout.print "No thread ##{num}\n"
      throw :debug_error
    end
    th
  end

  def thread_list(num)
    th = get_thread(num)
    if th == Thread.current
      @stdout.print "+"
    else
      @stdout.print " "
    end
    @stdout.printf "%d ", num
    @stdout.print th.inspect, "\t"
    file = context(th).instance_eval{@file}
    if file
      @stdout.print file,":",context(th).instance_eval{@line}
    end
    @stdout.print "\n"
  end

  def thread_list_all
    for th in @thread_list.values.sort
      thread_list(th)
    end
  end

  def make_thread_list
    hash = {}
    for th in Thread::list
      if @thread_list.key? th
	hash[th] = @thread_list[th]
      else
	@max_thread += 1
	hash[th] = @max_thread
      end
    end
    @thread_list = hash
  end

  def debug_thread_info(input, binding)
    case input
    when /^l(?:ist)?/
      make_thread_list
      thread_list_all

    when /^c(?:ur(?:rent)?)?$/
      make_thread_list
      thread_list(@thread_list[Thread.current])

    when /^(?:sw(?:itch)?\s+)?(\d+)/
      make_thread_list
      th = get_thread($1.to_i)
      if th == Thread.current
	@stdout.print "It's the current thread.\n"
      else
	thread_list(@thread_list[th])
	context(th).stop_next
	th.run
	return :cont
      end

    when /^stop\s+(\d+)/
      make_thread_list
      th = get_thread($1.to_i)
      if th == Thread.current
	@stdout.print "It's the current thread.\n"
      elsif th.stop?
	@stdout.print "Already stopped.\n"
      else
	thread_list(@thread_list[th])
	context(th).suspend 
      end

    when /^resume\s+(\d+)/
      make_thread_list
      th = get_thread($1.to_i)
      if th == Thread.current
	@stdout.print "It's the current thread.\n"
      elsif !th.stop?
	@stdout.print "Already running."
      else
	thread_list(@thread_list[th])
	th.run
      end
    end
  end
end

stdout.printf "Debug.rb\n"
stdout.printf "Emacs support available.\n\n"
set_trace_func proc { |event, file, line, id, binding, klass, *rest|
  DEBUGGER__.context.trace_func event, file, line, id, binding, klass
}
end