guard_condition.hpp

// Copyright 2020 Open Source Robotics Foundation, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#ifndef RCLCPP__GUARD_CONDITION_HPP_
#define RCLCPP__GUARD_CONDITION_HPP_
 
#include <atomic>
 
#include "rcl/guard_condition.h"
 
#include "rclcpp/context.hpp"
#include "rclcpp/contexts/default_context.hpp"
#include "rclcpp/macros.hpp"
#include "rclcpp/visibility_control.hpp"
 
namespace rclcpp
{
 
class GuardCondition
{
public:
  RCLCPP_SMART_PTR_DEFINITIONS_NOT_COPYABLE(GuardCondition)
 
  // TODO(wjwwood): support custom allocator, maybe restrict to polymorphic allocator
 
  RCLCPP_PUBLIC
  explicit GuardCondition(
    const rclcpp::Context::SharedPtr & context =
    rclcpp::contexts::get_global_default_context(),
    rcl_guard_condition_options_t guard_condition_options =
    rcl_guard_condition_get_default_options());
 
  RCLCPP_PUBLIC
  virtual
  ~GuardCondition();
 
  RCLCPP_PUBLIC
  rcl_guard_condition_t &
  get_rcl_guard_condition();
 
  RCLCPP_PUBLIC
  const rcl_guard_condition_t &
  get_rcl_guard_condition() const;
 
 
  RCLCPP_PUBLIC
  void
  trigger();
 
 
  RCLCPP_PUBLIC
  bool
  exchange_in_use_by_wait_set_state(bool in_use_state);
 
 
  RCLCPP_PUBLIC
  void
  add_to_wait_set(rcl_wait_set_t & wait_set);
 
 
  RCLCPP_PUBLIC
  void
  set_on_trigger_callback(std::function<void(size_t)> callback);
 
protected:
  rcl_guard_condition_t rcl_guard_condition_;
  std::atomic<bool> in_use_by_wait_set_{false};
  std::recursive_mutex reentrant_mutex_;
  std::function<void(size_t)> on_trigger_callback_{nullptr};
  size_t unread_count_{0};
  // the type of wait_set_ is actually rcl_wait_set_t *, but it's never
  // dereferenced, only compared to, so make it void * to avoid accidental use
  void * wait_set_{nullptr};
};
 
}  // namespace rclcpp
 
#endif  // RCLCPP__GUARD_CONDITION_HPP_