Added Florian Gross' latest version of Breakpointer and friends that fixes a variaty of bugs #441 [Florian Gross]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@492 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 601 insertions, 612 deletions

diff --git a/activesupport/lib/binding_of_caller.rb b/activesupport/lib/binding_of_caller.rb
index 759e760016..d18fbdef3d 100644
--- a/activesupport/lib/binding_of_caller.rb
+++ b/activesupport/lib/binding_of_caller.rb
@@ -1,85 +1,83 @@
-begin
-  require 'simplecc'
-rescue LoadError
-  class Continuation #:nodoc:
-    def self.create(*args, &block)
-      cc = nil; result = callcc {|c| cc = c; block.call(cc) if block and args.empty?}
-      result ||= args
-      return *[cc, *result]
-    end
-  end
-end
-
-class Binding #:nodoc:
-  # This method returns the binding of the method that called your
-  # method. It will raise an Exception when you're not inside a method.
-  #
-  # It's used like this:
-  #   def inc_counter(amount = 1)
-  #     Binding.of_caller do |binding|
-  #       # Create a lambda that will increase the variable 'counter'
-  #       # in the caller of this method when called.
-  #       inc = eval("lambda { |arg| counter += arg }", binding)
-  #       # We can refer to amount from inside this block safely.
-  #       inc.call(amount)
-  #     end
-  #     # No other statements can go here. Put them inside the block.
-  #   end
-  #   counter = 0
-  #   2.times { inc_counter }
-  #   counter # => 2
-  #
-  # Binding.of_caller must be the last statement in the method.
-  # This means that you will have to put everything you want to
-  # do after the call to Binding.of_caller into the block of it.
-  # This should be no problem however, because Ruby has closures.
-  # If you don't do this an Exception will be raised. Because of
-  # the way that Binding.of_caller is implemented it has to be
-  # done this way.
-  def self.of_caller(&block)
-    old_critical = Thread.critical
-    Thread.critical = true
-    count = 0
-    cc, result, error, extra_data = Continuation.create(nil, nil)
-    error.call if error
-
-    tracer = lambda do |*args|
-      type, context, extra_data = args[0], args[4], args
-      if type == "return"
-        count += 1
-        # First this method and then calling one will return --
-        # the trace event of the second event gets the context
-        # of the method which called the method that called this
-        # method.
-        if count == 2
-          # It would be nice if we could restore the trace_func
-          # that was set before we swapped in our own one, but
-          # this is impossible without overloading set_trace_func
-          # in current Ruby.
-          set_trace_func(nil)
-          cc.call(eval("binding", context), nil, extra_data)
-        end
-      elsif type == "line" then
-        nil
-      elsif type == "c-return" and extra_data[3] == :set_trace_func then
-        nil
-      else
-        set_trace_func(nil)
-        error_msg = "Binding.of_caller used in non-method context or " +
-          "trailing statements of method using it aren't in the block."
-        cc.call(nil, lambda { raise(ArgumentError, error_msg) }, nil)
-      end
-    end
-
-    unless result
-      set_trace_func(tracer)
-      return nil
-    else
-      Thread.critical = old_critical
-      case block.arity
-        when 1 then yield(result)
-        else yield(result, extra_data)        
-      end
-    end
-  end
-end
\ No newline at end of file
+begin

+  require 'simplecc'

+rescue LoadError

+  class Continuation; end # :nodoc: # for RDoc

+  def Continuation.create(*args, &block) # :nodoc:

+    cc = nil; result = callcc {|c| cc = c; block.call(cc) if block and args.empty?}

+    result ||= args

+    return *[cc, *result]

+  end

+end

+

+class Binding; end # for RDoc

+# This method returns the binding of the method that called your

+# method. It will raise an Exception when you're not inside a method.

+#

+# It's used like this:

+#   def inc_counter(amount = 1)

+#     Binding.of_caller do |binding|

+#       # Create a lambda that will increase the variable 'counter'

+#       # in the caller of this method when called.

+#       inc = eval("lambda { |arg| counter += arg }", binding)

+#       # We can refer to amount from inside this block safely.

+#       inc.call(amount)

+#     end

+#     # No other statements can go here. Put them inside the block.

+#   end

+#   counter = 0

+#   2.times { inc_counter }

+#   counter # => 2

+#

+# Binding.of_caller must be the last statement in the method.

+# This means that you will have to put everything you want to

+# do after the call to Binding.of_caller into the block of it.

+# This should be no problem however, because Ruby has closures.

+# If you don't do this an Exception will be raised. Because of

+# the way that Binding.of_caller is implemented it has to be

+# done this way.

+def Binding.of_caller(&block)

+  old_critical = Thread.critical

+  Thread.critical = true

+  count = 0

+  cc, result, error, extra_data = Continuation.create(nil, nil)

+  error.call if error

+

+  tracer = lambda do |*args|

+    type, context, extra_data = args[0], args[4], args

+    if type == "return"

+      count += 1

+      # First this method and then calling one will return --

+      # the trace event of the second event gets the context

+      # of the method which called the method that called this

+      # method.

+      if count == 2

+        # It would be nice if we could restore the trace_func

+        # that was set before we swapped in our own one, but

+        # this is impossible without overloading set_trace_func

+        # in current Ruby.

+        set_trace_func(nil)

+        cc.call(eval("binding", context), nil, extra_data)

+      end

+    elsif type == "line" then

+      nil

+    elsif type == "c-return" and extra_data[3] == :set_trace_func then

+      nil

+    else

+      set_trace_func(nil)

+      error_msg = "Binding.of_caller used in non-method context or " +

+        "trailing statements of method using it aren't in the block."

+      cc.call(nil, lambda { raise(ArgumentError, error_msg) }, nil)

+    end

+  end

+

+  unless result

+    set_trace_func(tracer)

+    return nil

+  else

+    Thread.critical = old_critical

+    case block.arity

+      when 1 then yield(result)

+      else yield(result, extra_data)        

+    end

+  end

+end

diff --git a/activesupport/lib/breakpoint.rb b/activesupport/lib/breakpoint.rb
index 75d55df20e..1923d49733 100755
--- a/activesupport/lib/breakpoint.rb
+++ b/activesupport/lib/breakpoint.rb
@@ -1,527 +1,518 @@
-# The Breakpoint library provides the convenience of
-# being able to inspect and modify state, diagnose
-# bugs all via IRB by simply setting breakpoints in
-# your applications by the call of a method.
-#
-# This library was written and is supported by me,
-# Florian Gross. I can be reached at flgr@ccan.de
-# and enjoy getting feedback about my libraries.
-#
-# The whole library (including breakpoint_client.rb
-# and binding_of_caller.rb) is licensed under the
-# same license that Ruby uses. (Which is currently
-# either the GNU General Public License or a custom
-# one that allows for commercial usage.) If you for
-# some good reason need to use this under another
-# license please contact me.
-
-require 'irb'
-# require 'binding_of_caller' <- Needs this
-require 'drb'
-require 'drb/acl'
-
-module Breakpoint
-  extend self
-
-  # This will pop up an interactive ruby session at a
-  # pre-defined break point in a Ruby application. In
-  # this session you can examine the environment of
-  # the break point.
-  #
-  # You can get a list of variables in the context using
-  # local_variables via +local_variables+. You can then
-  # examine their values by typing their names.
-  #
-  # You can have a look at the call stack via +caller+.
-  #
-  # The source code around the location where the breakpoint
-  # was executed can be examined via +source_lines+. Its
-  # argument specifies how much lines of context to display.
-  # The default amount of context is 5 lines. Note that
-  # the call to +source_lines+ can raise an exception when
-  # it isn't able to read in the source code.
-  #
-  # breakpoints can also return a value. They will execute
-  # a supplied block for getting a default return value.
-  # A custom value can be returned from the session by doing
-  # +throw(:debug_return, value)+.
-  #
-  # You can also give names to break points which will be
-  # used in the message that is displayed upon execution 
-  # of them.
-  #
-  # Here's a sample of how breakpoints should be placed:
-  #
-  #   class Person
-  #     def initialize(name, age)
-  #       @name, @age = name, age
-  #       breakpoint("Person#initialize")
-  #     end
-  #
-  #     attr_reader :age
-  #     def name
-  #       breakpoint("Person#name") { @name }
-  #     end
-  #   end
-  #
-  #   person = Person.new("Random Person", 23)
-  #   puts "Name: #{person.name}"
-  #
-  # And here is a sample debug session:
-  #
-  #   Executing break point "Person#initialize" at file.rb:4 in `initialize'
-  #   irb(#<Person:0x292fbe8>):001:0> local_variables
-  #   => ["name", "age", "_", "__"]
-  #   irb(#<Person:0x292fbe8>):002:0> [name, age]
-  #   => ["Random Person", 23]
-  #   irb(#<Person:0x292fbe8>):003:0> [@name, @age]
-  #   => ["Random Person", 23]
-  #   irb(#<Person:0x292fbe8>):004:0> self
-  #   => #<Person:0x292fbe8 @age=23, @name="Random Person">
-  #   irb(#<Person:0x292fbe8>):005:0> @age += 1; self
-  #   => #<Person:0x292fbe8 @age=24, @name="Random Person">
-  #   irb(#<Person:0x292fbe8>):006:0> exit
-  #   Executing break point "Person#name" at file.rb:9 in `name'
-  #   irb(#<Person:0x292fbe8>):001:0> throw(:debug_return, "Overriden name")
-  #   Name: Overriden name
-  #
-  # Breakpoint sessions will automatically have a few
-  # convenience methods available. See Breakpoint::CommandBundle
-  # for a list of them.
-  #
-  # Breakpoints can also be used remotely over sockets.
-  # This is implemented by running part of the IRB session
-  # in the application and part of it in a special client.
-  # You have to call Breakpoint.activate_drb to enable
-  # support for remote breakpoints and then run
-  # breakpoint_client.rb which is distributed with this
-  # library. See the documentation of Breakpoint.activate_drb
-  # for details.
-  def breakpoint(id = nil, context = nil, &block)
-    callstack = caller
-    callstack.slice!(0, 3) if callstack.first["breakpoint"]
-    file, line, method = *callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/).captures
-
-    message = "Executing break point " + (id ? "#{id.inspect} " : "") +
-              "at #{file}:#{line}" + (method ? " in `#{method}'" : "")
-
-    if context then
-      return handle_breakpoint(context, message, file, line, &block)
-    end
-
-    Binding.of_caller do |binding_context|
-      handle_breakpoint(binding_context, message, file, line, &block)
-    end
-  end
-
-  module CommandBundle #:nodoc:
-    # Proxy to a Breakpoint client. Lets you directly execute code
-    # in the context of the client.
-    class Client#:nodoc:
-      def initialize(eval_handler) # :nodoc:
-        @eval_handler = eval_handler
-      end
-
-      instance_methods.each do |method|
-        next if method[/^__.+__$/]
-        undef_method method
-      end
-
-      # Executes the specified code at the client.
-      def eval(code)
-        @eval_handler.call(code)
-      end
-
-      # Will execute the specified statement at the client.
-      def method_missing(method, *args)
-        if args.empty?
-          result = eval("#{method}")
-        else
-          result = eval("#{method}(*Marshal.load(#{Marshal.dump(args).inspect}))")
-        end
-
-        unless [true, false, nil].include?(result)
-          result.extend(DRbUndumped) if result
-        end
-
-        return result
-      end
-    end
-
-    # Returns the source code surrounding the location where the
-    # breakpoint was issued.
-    def source_lines(context = 5, return_line_numbers = false)
-      lines = File.readlines(@__bp_file).map { |line| line.chomp }
-
-      break_line = @__bp_line
-      start_line = [break_line - context, 1].max
-      end_line = break_line + context
-
-      result = lines[(start_line - 1) .. (end_line - 1)]
-
-      if return_line_numbers then
-        return [start_line, break_line, result]
-      else
-        return result
-      end
-    end
-
-    # Lets an object that will forward method calls to the breakpoint
-    # client. This is useful for outputting longer things at the client
-    # and so on. You can for example do these things:
-    #
-    #   client.puts "Hello" # outputs "Hello" at client console
-    #   # outputs "Hello" into the file temp.txt at the client
-    #   client.File.open("temp.txt", "w") { |f| f.puts "Hello" } 
-    def client()
-      if Breakpoint.use_drb? then
-        Client.new(Breakpoint.drb_service.eval_handler)
-      else
-        Client.new(lambda { |code| eval(code, TOPLEVEL_BINDING) })
-      end
-    end
-  end
-
-  def handle_breakpoint(context, message, file = "", line = "", &block) # :nodoc:
-    catch(:debug_return) do |value|
-      eval(%{
-        @__bp_file = #{file.inspect}
-        @__bp_line = #{line}
-        extend Breakpoint::CommandBundle
-        extend DRbUndumped if self
-      }, context) rescue nil
-
-      if not use_drb? then
-        puts message
-        IRB.start(nil, IRB::WorkSpace.new(context))
-      else
-        @drb_service.add_breakpoint(context, message)
-      end
-
-      block.call if block
-    end
-  end
-
-  # These exceptions will be raised on failed asserts
-  # if Breakpoint.asserts_cause_exceptions is set to
-  # true.
-  class FailedAssertError < RuntimeError#:nodoc:
-  end
-
-  # This asserts that the block evaluates to true.
-  # If it doesn't evaluate to true a breakpoint will
-  # automatically be created at that execution point.
-  #
-  # You can disable assert checking in production
-  # code by setting Breakpoint.optimize_asserts to
-  # true. (It will still be enabled when Ruby is run
-  # via the -d argument.)
-  #
-  # Example:
-  #   person_name = "Foobar"
-  #   assert { not person_name.nil? }
-  #
-  # Note: If you want to use this method from an
-  # unit test, you will have to call it by its full
-  # name, Breakpoint.assert.
-  def assert(context = nil, &condition)
-    return if Breakpoint.optimize_asserts and not $DEBUG
-    return if yield
-
-    callstack = caller
-    callstack.slice!(0, 3) if callstack.first["assert"]
-    file, line, method = *callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/).captures
-
-    message = "Assert failed at #{file}:#{line}#{" in `#{method}'" if method}."
-
-    if Breakpoint.asserts_cause_exceptions and not $DEBUG then
-      raise(Breakpoint::FailedAssertError, message)
-    end
-
-    message += " Executing implicit breakpoint."
-
-    if context then
-      return handle_breakpoint(context, message, file, line)
-    end
-
-    Binding.of_caller do |context|
-      handle_breakpoint(context, message, file, line)
-    end
-  end
-
-  # Whether asserts should be ignored if not in debug mode.
-  # Debug mode can be enabled by running ruby with the -d
-  # switch or by setting $DEBUG to true.
-  attr_accessor :optimize_asserts
-  self.optimize_asserts = false
-
-  # Whether an Exception should be raised on failed asserts
-  # in non-$DEBUG code or not. By default this is disabled.
-  attr_accessor :asserts_cause_exceptions
-  self.asserts_cause_exceptions = false
-  @use_drb = false
-
-  attr_reader :drb_service # :nodoc:
-
-  class DRbService # :nodoc:
-    include DRbUndumped
-
-    def initialize
-      @handler = @eval_handler = @collision_handler = nil
-
-      IRB.instance_eval { @CONF[:RC] = true }
-      IRB.run_config
-    end
-
-    def collision
-      sleep(0.5) until @collision_handler
-
-      @collision_handler.call
-    end
-
-    def ping; end
-
-    def add_breakpoint(context, message)
-      workspace = IRB::WorkSpace.new(context)
-      workspace.extend(DRbUndumped)
-
-      sleep(0.5) until @handler
-
-      @handler.call(workspace, message)
-    end
-
-    def register_handler(&block)
-      @handler = block
-    end
-
-    def unregister_handler
-      @handler = nil
-    end
-
-    attr_reader :eval_handler
-
-    def register_eval_handler(&block)
-      @eval_handler = block
-    end
-
-    def unregister_eval_handler
-      @eval_handler = lambda { }
-    end
-
-    def register_collision_handler(&block)
-      @collision_handler = block
-    end
-
-    def unregister_collision_handler
-      @collision_handler = lambda { }
-    end
-  end
-
-  # Will run Breakpoint in DRb mode. This will spawn a server
-  # that can be attached to via the breakpoint-client command
-  # whenever a breakpoint is executed. This is useful when you
-  # are debugging CGI applications or other applications where
-  # you can't access debug sessions via the standard input and
-  # output of your application.
-  #
-  # You can specify an URI where the DRb server will run at.
-  # This way you can specify the port the server runs on. The
-  # default URI is druby://localhost:42531.
-  #
-  # Please note that breakpoints will be skipped silently in
-  # case the DRb server can not spawned. (This can happen if
-  # the port is already used by another instance of your
-  # application on CGI or another application.)
-  #
-  # Also note that by default this will only allow access
-  # from localhost. You can however specify a list of
-  # allowed hosts or nil (to allow access from everywhere).
-  # But that will still not protect you from somebody
-  # reading the data as it goes through the net.
-  #
-  # A good approach for getting security and remote access
-  # is setting up an SSH tunnel between the DRb service
-  # and the client. This is usually done like this:
-  #
-  # $ ssh -L20000:127.0.0.1:20000 -R10000:127.0.0.1:10000 example.com
-  # (This will connect port 20000 at the client side to port
-  # 20000 at the server side, and port 10000 at the server
-  # side to port 10000 at the client side.)
-  #
-  # After that do this on the server side: (the code being debugged)
-  # Breakpoint.activate_drb("druby://127.0.0.1:20000", "localhost")
-  #
-  # And at the client side:
-  # ruby breakpoint_client.rb -c druby://127.0.0.1:10000 -s druby://127.0.0.1:20000
-  #
-  # Running through such a SSH proxy will also let you use 
-  # breakpoint.rb in case you are behind a firewall.
-  #
-  # Detailed information about running DRb through firewalls is
-  # available at http://www.rubygarden.org/ruby?DrbTutorial
-  def activate_drb(uri = nil, allowed_hosts = ['localhost', '127.0.0.1', '::1'], ignore_collisions = false) #:nodoc:
-
-    return false if @use_drb
-
-    uri ||= 'druby://localhost:42531'
-
-    if allowed_hosts then
-      acl = ["deny", "all"]
-
-      Array(allowed_hosts).each do |host|
-        acl += ["allow", host]
-      end
-
-      DRb.install_acl(ACL.new(acl))
-    end
-
-    @use_drb = true
-    @drb_service = DRbService.new
-    did_collision = false
-    begin
-      @service = DRb.start_service(uri, @drb_service)
-    rescue Errno::EADDRINUSE
-      if ignore_collisions then
-        nil
-      else
-        # The port is already occupied by another
-        # Breakpoint service. We will try to tell
-        # the old service that we want its port.
-        # It will then forward that request to the
-        # user and retry.
-        unless did_collision then
-          DRbObject.new(nil, uri).collision
-          did_collision = true
-        end
-        sleep(10)
-        retry
-      end
-    end
-
-    return true
-  end
-
-  # Deactivates a running Breakpoint service.
-  def deactivate_drb #:nodoc:
-    @service.stop_service unless @service.nil?
-    @service = nil
-    @use_drb = false
-    @drb_service = nil
-  end
-
-  # Returns true when Breakpoints are used over DRb.
-  # Breakpoint.activate_drb causes this to be true.
-  def use_drb? #:nodoc:
-    @use_drb == true
-  end
-end
-
-module IRB # :nodoc:
-  def IRB.parse_opts() end
-
-  class << self; remove_method :start; end
-  def self.start(ap_path = nil, main_context = nil, workspace = nil)
-    $0 = File::basename(ap_path, ".rb") if ap_path
-
-    # suppress some warnings about redefined constants
-    old_verbose, $VERBOSE = $VERBOSE, nil
-    IRB.setup(ap_path)
-    $VERBOSE = old_verbose
-
-    if @CONF[:SCRIPT] then
-      irb = Irb.new(main_context, @CONF[:SCRIPT])
-    else
-      irb = Irb.new(main_context)
-    end
-
-    if workspace then
-      irb.context.workspace = workspace
-    end
-
-    @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]
-    @CONF[:MAIN_CONTEXT] = irb.context
-
-    old_sigint = trap("SIGINT") do
-      irb.signal_handle
-    end
-    
-    catch(:IRB_EXIT) do
-      irb.eval_input
-    end
-  ensure
-    trap("SIGINT", old_sigint)
-  end
-
-  class << self
-    alias :old_CurrentContext :CurrentContext
-    remove_method :CurrentContext
-  end
-  def IRB.CurrentContext
-    if old_CurrentContext.nil? and Breakpoint.use_drb? then
-      result = Object.new
-      def result.last_value; end
-      return result
-    else
-      old_CurrentContext
-    end
-  end
-
-  class Context#:nodoc:
-    alias :old_evaluate :evaluate
-    def evaluate(line, line_no)
-      if line.chomp == "exit" then
-        exit
-      else
-        old_evaluate(line, line_no)
-      end
-    end
-  end
-
-  class WorkSpace#:nodoc:
-    alias :old_evaluate :evaluate
-
-    def evaluate(*args)
-      if Breakpoint.use_drb? then
-        result = old_evaluate(*args)
-        if args[0] != :no_proxy and
-          not [true, false, nil].include?(result)
-        then
-          result.extend(DRbUndumped) rescue nil
-        end
-        return result
-      else
-        old_evaluate(*args)
-      end
-    end
-  end
-
-  module InputCompletor#:nodoc:
-    def self.eval(code, context, *more)
-      # Big hack, this assumes that InputCompletor
-      # will only call eval() when it wants code
-      # to be executed in the IRB context.
-      IRB.conf[:MAIN_CONTEXT].workspace.evaluate(:no_proxy, code, *more)
-    end
-  end
-end
-
-module DRb # :nodoc:
-  class DRbObject#:nodoc:
-    undef :inspect
-    undef :clone
-  end
-end
-
-# See Breakpoint.breakpoint
-def breakpoint(id = nil, &block)
-  Binding.of_caller do |context|
-    Breakpoint.breakpoint(id, context, &block)
-  end
-end
-
-# See Breakpoint.assert
-def assert(&block)
-  Binding.of_caller do |context|
-    Breakpoint.assert(context, &block)
-  end
-end
\ No newline at end of file
+# The Breakpoint library provides the convenience of

+# being able to inspect and modify state, diagnose

+# bugs all via IRB by simply setting breakpoints in

+# your applications by the call of a method.

+#

+# This library was written and is supported by me,

+# Florian Gross. I can be reached at flgr@ccan.de

+# and enjoy getting feedback about my libraries.

+#

+# The whole library (including breakpoint_client.rb

+# and binding_of_caller.rb) is licensed under the

+# same license that Ruby uses. (Which is currently

+# either the GNU General Public License or a custom

+# one that allows for commercial usage.) If you for

+# some good reason need to use this under another

+# license please contact me.

+

+require 'irb'

+require 'binding_of_caller'

+require 'drb'

+require 'drb/acl'

+

+module Breakpoint

+  id = %q$Id: breakpoint.rb 41 2005-01-22 20:22:10Z flgr $

+  Version = id.split(" ")[2].to_i

+

+  extend self

+

+  # This will pop up an interactive ruby session at a

+  # pre-defined break point in a Ruby application. In

+  # this session you can examine the environment of

+  # the break point.

+  #

+  # You can get a list of variables in the context using

+  # local_variables via +local_variables+. You can then

+  # examine their values by typing their names.

+  #

+  # You can have a look at the call stack via +caller+.

+  #

+  # The source code around the location where the breakpoint

+  # was executed can be examined via +source_lines+. Its

+  # argument specifies how much lines of context to display.

+  # The default amount of context is 5 lines. Note that

+  # the call to +source_lines+ can raise an exception when

+  # it isn't able to read in the source code.

+  #

+  # breakpoints can also return a value. They will execute

+  # a supplied block for getting a default return value.

+  # A custom value can be returned from the session by doing

+  # +throw(:debug_return, value)+.

+  #

+  # You can also give names to break points which will be

+  # used in the message that is displayed upon execution 

+  # of them.

+  #

+  # Here's a sample of how breakpoints should be placed:

+  #

+  #   class Person

+  #     def initialize(name, age)

+  #       @name, @age = name, age

+  #       breakpoint("Person#initialize")

+  #     end

+  #

+  #     attr_reader :age

+  #     def name

+  #       breakpoint("Person#name") { @name }

+  #     end

+  #   end

+  #

+  #   person = Person.new("Random Person", 23)

+  #   puts "Name: #{person.name}"

+  #

+  # And here is a sample debug session:

+  #

+  #   Executing break point "Person#initialize" at file.rb:4 in `initialize'

+  #   irb(#<Person:0x292fbe8>):001:0> local_variables

+  #   => ["name", "age", "_", "__"]

+  #   irb(#<Person:0x292fbe8>):002:0> [name, age]

+  #   => ["Random Person", 23]

+  #   irb(#<Person:0x292fbe8>):003:0> [@name, @age]

+  #   => ["Random Person", 23]

+  #   irb(#<Person:0x292fbe8>):004:0> self

+  #   => #<Person:0x292fbe8 @age=23, @name="Random Person">

+  #   irb(#<Person:0x292fbe8>):005:0> @age += 1; self

+  #   => #<Person:0x292fbe8 @age=24, @name="Random Person">

+  #   irb(#<Person:0x292fbe8>):006:0> exit

+  #   Executing break point "Person#name" at file.rb:9 in `name'

+  #   irb(#<Person:0x292fbe8>):001:0> throw(:debug_return, "Overriden name")

+  #   Name: Overriden name

+  #

+  # Breakpoint sessions will automatically have a few

+  # convenience methods available. See Breakpoint::CommandBundle

+  # for a list of them.

+  #

+  # Breakpoints can also be used remotely over sockets.

+  # This is implemented by running part of the IRB session

+  # in the application and part of it in a special client.

+  # You have to call Breakpoint.activate_drb to enable

+  # support for remote breakpoints and then run

+  # breakpoint_client.rb which is distributed with this

+  # library. See the documentation of Breakpoint.activate_drb

+  # for details.

+  def breakpoint(id = nil, context = nil, &block)

+    callstack = caller

+    callstack.slice!(0, 3) if callstack.first["breakpoint"]

+    file, line, method = *callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/).captures

+

+    message = "Executing break point " + (id ? "#{id.inspect} " : "") +

+              "at #{file}:#{line}" + (method ? " in `#{method}'" : "")

+

+    if context then

+      return handle_breakpoint(context, message, file, line, &block)

+    end

+

+    Binding.of_caller do |binding_context|

+      handle_breakpoint(binding_context, message, file, line, &block)

+    end

+  end

+

+  module CommandBundle

+    # Proxy to a Breakpoint client. Lets you directly execute code

+    # in the context of the client.

+    class Client

+      def initialize(eval_handler) # :nodoc:

+        @eval_handler = eval_handler

+      end

+

+      instance_methods.each do |method|

+        next if method[/^__.+__$/]

+        undef_method method

+      end

+

+      # Executes the specified code at the client.

+      def eval(code)

+        @eval_handler.call(code)

+      end

+

+      # Will execute the specified statement at the client.

+      def method_missing(method, *args, &block)

+        if args.empty? and not block

+          result = eval "#{method}"

+        else

+          # This is a bit ugly. The alternative would be using an

+          # eval context instead of an eval handler for executing

+          # the code at the client. The problem with that approach

+          # is that we would have to handle special expressions

+          # like "self", "nil" or constants ourself which is hard.

+          remote = eval %{

+            result = lambda { |block, *args| #{method}(*args, &block) }

+            def result.call_with_block(*args, &block)

+              call(block, *args)

+            end

+            result

+          }

+          remote.call_with_block(*args, &block)

+        end

+

+        return result

+      end

+    end

+

+    # Returns the source code surrounding the location where the

+    # breakpoint was issued.

+    def source_lines(context = 5, return_line_numbers = false)

+      lines = File.readlines(@__bp_file).map { |line| line.chomp }

+

+      break_line = @__bp_line

+      start_line = [break_line - context, 1].max

+      end_line = break_line + context

+

+      result = lines[(start_line - 1) .. (end_line - 1)]

+

+      if return_line_numbers then

+        return [start_line, break_line, result]

+      else

+        return result

+      end

+    end

+

+    # Lets an object that will forward method calls to the breakpoint

+    # client. This is useful for outputting longer things at the client

+    # and so on. You can for example do these things:

+    #

+    #   client.puts "Hello" # outputs "Hello" at client console

+    #   # outputs "Hello" into the file temp.txt at the client

+    #   client.File.open("temp.txt", "w") { |f| f.puts "Hello" } 

+    def client()

+      if Breakpoint.use_drb? then

+        sleep(0.5) until Breakpoint.drb_service.eval_handler

+        Client.new(Breakpoint.drb_service.eval_handler)

+      else

+        Client.new(lambda { |code| eval(code, TOPLEVEL_BINDING) })

+      end

+    end

+  end

+

+  def handle_breakpoint(context, message, file = "", line = "", &block) # :nodoc:

+    catch(:debug_return) do |value|

+      eval(%{

+        @__bp_file = #{file.inspect}

+        @__bp_line = #{line}

+        extend Breakpoint::CommandBundle

+        extend DRbUndumped if self

+      }, context) rescue nil

+

+      if not use_drb? then

+        puts message

+        IRB.start(nil, IRB::WorkSpace.new(context))

+      else

+        @drb_service.add_breakpoint(context, message)

+      end

+

+      block.call if block

+    end

+  end

+

+  # These exceptions will be raised on failed asserts

+  # if Breakpoint.asserts_cause_exceptions is set to

+  # true.

+  class FailedAssertError < RuntimeError

+  end

+

+  # This asserts that the block evaluates to true.

+  # If it doesn't evaluate to true a breakpoint will

+  # automatically be created at that execution point.

+  #

+  # You can disable assert checking in production

+  # code by setting Breakpoint.optimize_asserts to

+  # true. (It will still be enabled when Ruby is run

+  # via the -d argument.)

+  #

+  # Example:

+  #   person_name = "Foobar"

+  #   assert { not person_name.nil? }

+  #

+  # Note: If you want to use this method from an

+  # unit test, you will have to call it by its full

+  # name, Breakpoint.assert.

+  def assert(context = nil, &condition)

+    return if Breakpoint.optimize_asserts and not $DEBUG

+    return if yield

+

+    callstack = caller

+    callstack.slice!(0, 3) if callstack.first["assert"]

+    file, line, method = *callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/).captures

+

+    message = "Assert failed at #{file}:#{line}#{" in `#{method}'" if method}."

+

+    if Breakpoint.asserts_cause_exceptions and not $DEBUG then

+      raise(Breakpoint::FailedAssertError, message)

+    end

+

+    message += " Executing implicit breakpoint."

+

+    if context then

+      return handle_breakpoint(context, message, file, line)

+    end

+

+    Binding.of_caller do |context|

+      handle_breakpoint(context, message, file, line)

+    end

+  end

+

+  # Whether asserts should be ignored if not in debug mode.

+  # Debug mode can be enabled by running ruby with the -d

+  # switch or by setting $DEBUG to true.

+  attr_accessor :optimize_asserts

+  self.optimize_asserts = false

+

+  # Whether an Exception should be raised on failed asserts

+  # in non-$DEBUG code or not. By default this is disabled.

+  attr_accessor :asserts_cause_exceptions

+  self.asserts_cause_exceptions = false

+  @use_drb = false

+

+  attr_reader :drb_service # :nodoc:

+

+  class DRbService # :nodoc:

+    include DRbUndumped

+

+    def initialize

+      @handler = @eval_handler = @collision_handler = nil

+

+      IRB.instance_eval { @CONF[:RC] = true }

+      IRB.run_config

+    end

+

+    def collision

+      sleep(0.5) until @collision_handler

+

+      @collision_handler.call

+    end

+

+    def ping() end

+

+    def add_breakpoint(context, message)

+      workspace = IRB::WorkSpace.new(context)

+      workspace.extend(DRbUndumped)

+

+      sleep(0.5) until @handler

+

+      @handler.call(workspace, message)

+    end

+

+    attr_accessor :handler, :eval_handler, :collision_handler

+  end

+

+  # Will run Breakpoint in DRb mode. This will spawn a server

+  # that can be attached to via the breakpoint-client command

+  # whenever a breakpoint is executed. This is useful when you

+  # are debugging CGI applications or other applications where

+  # you can't access debug sessions via the standard input and

+  # output of your application.

+  #

+  # You can specify an URI where the DRb server will run at.

+  # This way you can specify the port the server runs on. The

+  # default URI is druby://localhost:42531.

+  #

+  # Please note that breakpoints will be skipped silently in

+  # case the DRb server can not spawned. (This can happen if

+  # the port is already used by another instance of your

+  # application on CGI or another application.)

+  #

+  # Also note that by default this will only allow access

+  # from localhost. You can however specify a list of

+  # allowed hosts or nil (to allow access from everywhere).

+  # But that will still not protect you from somebody

+  # reading the data as it goes through the net.

+  #

+  # A good approach for getting security and remote access

+  # is setting up an SSH tunnel between the DRb service

+  # and the client. This is usually done like this:

+  #

+  # $ ssh -L20000:127.0.0.1:20000 -R10000:127.0.0.1:10000 example.com

+  # (This will connect port 20000 at the client side to port

+  # 20000 at the server side, and port 10000 at the server

+  # side to port 10000 at the client side.)

+  #

+  # After that do this on the server side: (the code being debugged)

+  # Breakpoint.activate_drb("druby://127.0.0.1:20000", "localhost")

+  #

+  # And at the client side:

+  # ruby breakpoint_client.rb -c druby://127.0.0.1:10000 -s druby://127.0.0.1:20000

+  #

+  # Running through such a SSH proxy will also let you use 

+  # breakpoint.rb in case you are behind a firewall.

+  #

+  # Detailed information about running DRb through firewalls is

+  # available at http://www.rubygarden.org/ruby?DrbTutorial

+  def activate_drb(uri = nil, allowed_hosts = ['localhost', '127.0.0.1', '::1'],

+    ignore_collisions = false)

+

+    return false if @use_drb

+

+    uri ||= 'druby://localhost:42531'

+

+    if allowed_hosts then

+      acl = ["deny", "all"]

+

+      Array(allowed_hosts).each do |host|

+        acl += ["allow", host]

+      end

+

+      DRb.install_acl(ACL.new(acl))

+    end

+

+    @use_drb = true

+    @drb_service = DRbService.new

+    did_collision = false

+    begin

+      @service = DRb.start_service(uri, @drb_service)

+    rescue Errno::EADDRINUSE

+      if ignore_collisions then

+        nil

+      else

+        # The port is already occupied by another

+        # Breakpoint service. We will try to tell

+        # the old service that we want its port.

+        # It will then forward that request to the

+        # user and retry.

+        unless did_collision then

+          DRbObject.new(nil, uri).collision

+          did_collision = true

+        end

+        sleep(10)

+        retry

+      end

+    end

+

+    return true

+  end

+

+  # Deactivates a running Breakpoint service.

+  def deactivate_drb

+    @service.stop_service unless @service.nil?

+    @service = nil

+    @use_drb = false

+    @drb_service = nil

+  end

+

+  # Returns true when Breakpoints are used over DRb.

+  # Breakpoint.activate_drb causes this to be true.

+  def use_drb?

+    @use_drb == true

+  end

+end

+

+module IRB # :nodoc:

+  class << self; remove_method :start; end

+  def self.start(ap_path = nil, main_context = nil, workspace = nil)

+    $0 = File::basename(ap_path, ".rb") if ap_path

+

+    # suppress some warnings about redefined constants

+    old_verbose, $VERBOSE = $VERBOSE, nil

+    IRB.setup(ap_path)

+    $VERBOSE = old_verbose

+

+    if @CONF[:SCRIPT] then

+      irb = Irb.new(main_context, @CONF[:SCRIPT])

+    else

+      irb = Irb.new(main_context)

+    end

+

+    if workspace then

+      irb.context.workspace = workspace

+    end

+

+    @CONF[:IRB_RC].call(irb.context) if @CONF[:IRB_RC]

+    @CONF[:MAIN_CONTEXT] = irb.context

+

+    old_sigint = trap("SIGINT") do

+      begin

+        irb.signal_handle

+      rescue RubyLex::TerminateLineInput

+        # ignored

+      end

+    end

+    

+    catch(:IRB_EXIT) do

+      irb.eval_input

+    end

+  ensure

+    trap("SIGINT", old_sigint)

+  end

+

+  class << self

+    alias :old_CurrentContext :CurrentContext

+    remove_method :CurrentContext

+  end

+  def IRB.CurrentContext

+    if old_CurrentContext.nil? and Breakpoint.use_drb? then

+      result = Object.new

+      def result.last_value; end

+      return result

+    else

+      old_CurrentContext

+    end

+  end

+

+  class Context

+    alias :old_evaluate :evaluate

+    def evaluate(line, line_no)

+      if line.chomp == "exit" then

+        exit

+      else

+        old_evaluate(line, line_no)

+      end

+    end

+  end

+

+  class WorkSpace

+    alias :old_evaluate :evaluate

+

+    def evaluate(*args)

+      if Breakpoint.use_drb? then

+        result = old_evaluate(*args)

+        if args[0] != :no_proxy and

+          not [true, false, nil].include?(result)

+        then

+          result.extend(DRbUndumped) rescue nil

+        end

+        return result

+      else

+        old_evaluate(*args)

+      end

+    end

+  end

+

+  module InputCompletor

+    def self.eval(code, context, *more)

+      # Big hack, this assumes that InputCompletor

+      # will only call eval() when it wants code

+      # to be executed in the IRB context.

+      IRB.conf[:MAIN_CONTEXT].workspace.evaluate(:no_proxy, code, *more)

+    end

+  end

+end

+

+module DRb # :nodoc:

+  class DRbObject

+    undef :inspect if method_defined?(:inspect)

+    undef :clone if method_defined?(:clone)

+  end

+end

+

+# See Breakpoint.breakpoint

+def breakpoint(id = nil, &block)

+  Binding.of_caller do |context|

+    Breakpoint.breakpoint(id, context, &block)

+  end

+end

+

+# See Breakpoint.assert

+def assert(&block)

+  Binding.of_caller do |context|

+    Breakpoint.assert(context, &block)

+  end

+end