Class: AppMap::Hook::Method

Inherits:
Object show all
Defined in:
lib/appmap/hook/method.rb

Constant Summary collapse

ARRAY_OF_EMPTY_HASH = 
[{}.freeze].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(hook_package, hook_class, hook_method) ⇒ Method

Returns a new instance of Method.



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# File 'lib/appmap/hook/method.rb', line 45

def initialize(hook_package, hook_class, hook_method)
  @hook_package = hook_package
  @hook_class = hook_class
  @hook_method = hook_method

  # Get the class for the method, if it's known.
  @defined_class, method_symbol = Hook.qualify_method_name(@hook_method)
  @method_display_name = [@defined_class, method_symbol, @hook_method.name].join if @defined_class
end

Instance Attribute Details

#hook_class ⇒ Object (readonly)

Returns the value of attribute hook_class.



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# File 'lib/appmap/hook/method.rb', line 28

def hook_class
  @hook_class
end

#hook_method ⇒ Object (readonly)

Returns the value of attribute hook_method.



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# File 'lib/appmap/hook/method.rb', line 28

def hook_method
  @hook_method
end

#hook_package ⇒ Object (readonly)

Returns the value of attribute hook_package.



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# File 'lib/appmap/hook/method.rb', line 28

def hook_package
  @hook_package
end

#method_display_name ⇒ Object (readonly)

method_display_name may be nil if name resolution gets deferred until runtime (e.g. for a singleton method on an embedded Struct).



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# File 'lib/appmap/hook/method.rb', line 33

def method_display_name
  @method_display_name
end

Instance Method Details

#activate ⇒ Object 



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# File 'lib/appmap/hook/method.rb', line 55

def activate
  if Hook::LOG
    msg = if method_display_name
            "#{method_display_name}"
          else
            "#{hook_method.name} (class resolution deferred)"
          end
    warn "AppMap: Hooking #{msg} at line #{(hook_method.source_location || []).join(':')}"
  end

  defined_class = @defined_class
  hook_package = self.hook_package
  hook_method = self.hook_method
  before_hook = self.method(:before_hook)
  after_hook = self.method(:after_hook)
  with_disabled_hook = self.method(:with_disabled_hook)

  is_array_containing_empty_hash = ->(obj) {
    obj.is_a?(Array) && obj.length == 1 && obj[0].is_a?(Hash) && obj[0].size == 0
  }

  call_instance_method = lambda do |receiver, args, &block|
    # https://github.com/applandinc/appmap-ruby/issues/153
    if NEW_RUBY && is_array_containing_empty_hash.(args) && hook_method.arity == 1
      hook_method.bind_call(receiver, {}, &block)
    else
      if NEW_RUBY
        hook_method.bind_call(receiver, *args, &block)
      else
        hook_method.bind(receiver).call(*args, &block)
      end
    end
  end

  hook_method_def = Proc.new do |*args, &block|
    # We may not have gotten the class for the method during
    # initialization (e.g. for a singleton method on an embedded
    # struct), so make sure we have it now.
    defined_class, = Hook.qualify_method_name(hook_method) unless defined_class

    reentrant = Thread.current[HOOK_DISABLE_KEY]
    disabled_by_shallow_flag = \
      -> { hook_package&.shallow? && AppMap.tracing.last_package_for_current_thread == hook_package }

    enabled = true if AppMap.tracing.enabled? && !reentrant && !disabled_by_shallow_flag.call

    enabled = false if %i[instance_eval instance_exec].member?(hook_method.name) && args.empty?

    return call_instance_method.call(self, args, &block) unless enabled

    call_event, start_time = with_disabled_hook.call do
      before_hook.call(self, defined_class, args)
    end
    return_value = nil
    exception = nil
    begin
      return_value = call_instance_method.call(self, args, &block)
    rescue
      exception = $ERROR_INFO
      raise
    ensure
      with_disabled_hook.call do
        after_hook.call(self, call_event, start_time, return_value, exception) if call_event
      end
    end
  end
  hook_method_def = hook_method_def.ruby2_keywords if hook_method_def.respond_to?(:ruby2_keywords)

  hook_method_parameters = hook_method.parameters.dup.freeze
  SIGNATURES[[ hook_class, hook_method.name ]] = hook_method_parameters

  # irb(main):001:0> Kernel.public_instance_method(:system)
  # (irb):1:in `public_instance_method': method `system' for module `Kernel' is  private (NameError)
  if hook_class == Kernel
    hook_class.define_method_with_arity(hook_method.name, hook_method.arity, hook_method_def)
  else
    hook_class.ancestors.find { |cls| cls.method_defined?(hook_method.name, false) }.tap do |cls|
      if cls
        cls.define_method_with_arity(hook_method.name, hook_method.arity, hook_method_def)
      else
        warn "#{hook_method.name} not found on #{hook_class}"
      end
    end
  end
end