Class: AppMap::Hook

Inherits:
Object
  • Object
show all
Defined in:
lib/appmap/hook.rb,
lib/appmap/hook/method.rb,
ext/appmap/appmap.c

Defined Under Namespace

Classes: Method

Constant Summary collapse

LOG = 
(ENV['APPMAP_DEBUG'] == 'true' || ENV['DEBUG'] == 'true')

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ Hook

Returns a new instance of Hook.



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# File 'lib/appmap/hook.rb', line 32

def initialize(config)
  @config = config
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/appmap/hook.rb', line 31

def config
  @config
end

Class Method Details

.lock_builtins ⇒ Object 



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# File 'lib/appmap/hook.rb', line 13

def lock_builtins
  return if @builtins_hooked

  @builtins_hooked = true
end

.qualify_method_name(method) ⇒ Object

Return the class, separator (‘.’ or ‘#’), and method name for the given method.



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# File 'lib/appmap/hook.rb', line 21

def qualify_method_name(method)
  if method.owner.singleton_class?
    class_name = singleton_method_owner_name(method)
    [ class_name, '.', method.name ]
  else
    [ method.owner.name, '#', method.name ]
  end
end

.singleton_method_owner_name(method) ⇒ Object 



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# File 'ext/appmap/appmap.c', line 15

static VALUE
singleton_method_owner_name(VALUE klass, VALUE method)
{
  VALUE owner = rb_funcall(method, rb_intern("owner"), 0);
  VALUE attached = rb_ivar_get(owner, rb_intern("__attached__"));
  if (!CLASS_OR_MODULE_P(attached)) {
    attached = rb_funcall(attached, rb_intern("class"), 0);
  }

  // Did __attached__.class return an object that's a Module or a
  // Class?
  if (CLASS_OR_MODULE_P(attached)) {
    // Yup, get it's name
    return rb_mod_name(attached);
  }

  // Nope (which seems weird, but whatever). Fall back to calling
  // #to_s on the method's owner and hope for the best.
  return rb_funcall(owner, rb_intern("to_s"), 0);
}

Instance Method Details

#enable(&block) ⇒ Object

Observe class loading and hook all methods which match the config.



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# File 'lib/appmap/hook.rb', line 37

def enable &block
  require 'appmap/hook/method'

  hook_builtins

  tp = TracePoint.new(:end) do |trace_point|
    cls = trace_point.self

    instance_methods = cls.public_instance_methods(false)
    class_methods = cls.singleton_class.public_instance_methods(false) - instance_methods

    hook = lambda do |hook_cls|
      lambda do |method_id|
        method = hook_cls.public_instance_method(method_id)

        warn "AppMap: Examining #{hook_cls} #{method.name}" if LOG

        disasm = RubyVM::InstructionSequence.disasm(method)
        # Skip methods that have no instruction sequence, as they are obviously trivial.
        next unless disasm

        next unless \
          config.always_hook?(hook_cls, method.name) ||
          config.included_by_location?(method)

        hook_method = Hook::Method.new(config.package_for_method(method), hook_cls, method)

        # Don't try and trace the AppMap methods or there will be
        # a stack overflow in the defined hook method.
        next if /\AAppMap[:\.]/.match?(hook_method.method_display_name)

        hook_method.activate
      end
    end

    instance_methods.each(&hook.(cls))
    class_methods.each(&hook.(cls.singleton_class))
  end

  tp.enable(&block)
end

#hook_builtins ⇒ Object 



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# File 'lib/appmap/hook.rb', line 79

def hook_builtins
  return unless self.class.lock_builtins

  class_from_string = lambda do |fq_class|
    fq_class.split('::').inject(Object) do |mod, class_name|
      mod.const_get(class_name)
    end
  end

  Config::BUILTIN_METHODS.each do |class_name, hook|
    require hook.package.package_name if hook.package.package_name
    Array(hook.method_names).each do |method_name|
      method_name = method_name.to_sym
      cls = class_from_string.(class_name)
      method = \
        begin
          cls.instance_method(method_name)
        rescue NameError
          cls.method(method_name) rescue nil
        end

      if method
        Hook::Method.new(hook.package, cls, method).activate
      else
        warn "Method #{method_name} not found on #{cls.name}"
      end
    end
  end
end