Class: AppMap::Hook::Method

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

Direct Known Subclasses

Rails::RequestHandler::HookMethod

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 21

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 6

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 6

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 6

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 11

def method_display_name
  @method_display_name
end

Instance Method Details

#activate ⇒ Object 



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

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
  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)

  hook_method_def = nil
  hook_class.instance_eval do 
    hook_method_def = Proc.new do |*args, &block|
      instance_method = hook_method.bind(self).to_proc
      call_instance_method = -> { instance_method.call(*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

      return call_instance_method.call 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
      rescue
        exception = $ERROR_INFO
        raise
      ensure
        with_disabled_hook.call do
          after_hook.call(self, call_event, start_time, return_value, exception)
        end
      end
    end
  end
  hook_class.define_method_with_arity(hook_method.name, hook_method.arity, hook_method_def)
end