buffer_core.h

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/*
 * Copyright (c) 2008, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 */
 
#ifndef TF2_BUFFER_CORE_H
#define TF2_BUFFER_CORE_H
 
#include "LinearMath/Transform.h"
#include "transform_storage.h"
 
#include <algorithm>
#include <cmath>
#include <string>
 
//#include "geometry_msgs/TwistStamped.h"
#include "geometry_msgs/msg/transform_stamped.hpp"
 
#include <map>
#include <unordered_map>
#include <mutex>
#include <functional>
#include <memory>
 
#include <tf2/exceptions.h>
#include <tf2/buffer_core_interface.h>
#include <tf2/visibility_control.h>
 
namespace tf2
{
 
typedef std::pair<TimePoint, CompactFrameID> P_TimeAndFrameID;
typedef uint32_t TransformableCallbackHandle;
typedef uint64_t TransformableRequestHandle;
 
class TimeCacheInterface;
using TimeCacheInterfacePtr = std::shared_ptr<TimeCacheInterface>;
 
enum TransformableResult
{
  TransformAvailable,
  TransformFailure,
};
 
 
static constexpr Duration BUFFER_CORE_DEFAULT_CACHE_TIME = std::chrono::seconds(10);  
 
class BufferCore : public BufferCoreInterface
{
public:
  /************* Constants ***********************/
  TF2_PUBLIC
  static const uint32_t MAX_GRAPH_DEPTH = 1000UL;  
 
  TF2_PUBLIC
  BufferCore(tf2::Duration cache_time_ = BUFFER_CORE_DEFAULT_CACHE_TIME);
 
  TF2_PUBLIC
  virtual ~BufferCore(void);
 
  TF2_PUBLIC
  void clear() override;
 
  TF2_PUBLIC
  bool setTransform(const geometry_msgs::msg::TransformStamped& transform, const std::string & authority, bool is_static = false);
 
  /*********** Accessors *************/
 
  TF2_PUBLIC
  geometry_msgs::msg::TransformStamped 
    lookupTransform(const std::string& target_frame, const std::string& source_frame,
            const TimePoint& time) const override;
 
  TF2_PUBLIC
  geometry_msgs::msg::TransformStamped
    lookupTransform(const std::string& target_frame, const TimePoint& target_time,
            const std::string& source_frame, const TimePoint& source_time,
            const std::string& fixed_frame) const override;
 
  /*
  geometry_msgs::Twist
    lookupTwist(const std::string& tracking_frame, const std::string& observation_frame, const std::string& reference_frame,
        const tf::Point & reference_point, const std::string& reference_point_frame, 
        const tf2::TimePoint& time, const tf2::Duration& averaging_interval) const;
  */
  /*
  geometry_msgs::Twist
    lookupTwist(const std::string& tracking_frame, const std::string& observation_frame, 
        const tf2::TimePoint& time, const tf2::Duration& averaging_interval) const;
  */
  TF2_PUBLIC
  bool canTransform(const std::string& target_frame, const std::string& source_frame,
                    const TimePoint& time, std::string* error_msg = NULL) const override;
  
  TF2_PUBLIC
  bool canTransform(const std::string& target_frame, const TimePoint& target_time,
                    const std::string& source_frame, const TimePoint& source_time,
                    const std::string& fixed_frame, std::string* error_msg = NULL) const override;
 
  TF2_PUBLIC
  std::vector<std::string> getAllFrameNames() const override;
 
  TF2_PUBLIC
  std::string allFramesAsYAML(TimePoint current_time) const;
 
  TF2_PUBLIC
  std::string allFramesAsYAML() const;
 
  TF2_PUBLIC
  std::string allFramesAsString() const;
 
  using TransformableCallback = std::function<void(TransformableRequestHandle request_handle, const std::string& target_frame, const std::string& source_frame,
                                                   TimePoint time, TransformableResult result)>;
 
  TF2_PUBLIC
  TransformableCallbackHandle addTransformableCallback(const TransformableCallback& cb);
  TF2_PUBLIC
  void removeTransformableCallback(TransformableCallbackHandle handle);
  TF2_PUBLIC
  TransformableRequestHandle addTransformableRequest(TransformableCallbackHandle handle, const std::string& target_frame, const std::string& source_frame, TimePoint time);
  TF2_PUBLIC
  void cancelTransformableRequest(TransformableRequestHandle handle);
 
 
 
 
  // Tell the buffer that there are multiple threads serviciing it. 
  // This is useful for derived classes to know if they can block or not. 
  TF2_PUBLIC
  void setUsingDedicatedThread(bool value) { using_dedicated_thread_ = value;};
  // Get the state of using_dedicated_thread_
  TF2_PUBLIC
  bool isUsingDedicatedThread() const { return using_dedicated_thread_;};
  
 
 
 
  /* Backwards compatability section for tf::Transformer you should not use these
   */
 
  TF2_PUBLIC
  bool _frameExists(const std::string& frame_id_str) const;
 
  TF2_PUBLIC
  bool _getParent(const std::string& frame_id, TimePoint time, std::string& parent) const;
 
  TF2_PUBLIC
  void _getFrameStrings(std::vector<std::string>& ids) const;
 
 
  TF2_PUBLIC
  CompactFrameID _lookupFrameNumber(const std::string& frameid_str) const { 
    return lookupFrameNumber(frameid_str); 
  }
  TF2_PUBLIC
  CompactFrameID _lookupOrInsertFrameNumber(const std::string& frameid_str) {
    return lookupOrInsertFrameNumber(frameid_str); 
  }
 
  TF2_PUBLIC
  tf2::TF2Error _getLatestCommonTime(CompactFrameID target_frame, CompactFrameID source_frame, TimePoint& time, std::string* error_string) const {
    std::unique_lock<std::mutex> lock(frame_mutex_);
    return getLatestCommonTime(target_frame, source_frame, time, error_string);
  }
 
  TF2_PUBLIC
  CompactFrameID _validateFrameId(const char* function_name_arg, const std::string& frame_id) const {
    return validateFrameId(function_name_arg, frame_id);
  }
 
  TF2_PUBLIC
  tf2::Duration getCacheLength() { return cache_time_;}
 
  TF2_PUBLIC
  std::string _allFramesAsDot(TimePoint current_time) const;
  TF2_PUBLIC
  std::string _allFramesAsDot() const;
 
  TF2_PUBLIC
  void _chainAsVector(const std::string & target_frame, TimePoint target_time, const std::string & source_frame, TimePoint source_time, const std::string & fixed_frame, std::vector<std::string>& output) const;
 
private:
 
  std::string allFramesAsStringNoLock() const;  
 
 
  /******************** Internal Storage ****************/
  
  typedef std::vector<TimeCacheInterfacePtr> V_TimeCacheInterface;
  V_TimeCacheInterface frames_;
  
  mutable std::mutex frame_mutex_;
 
  typedef std::unordered_map<std::string, CompactFrameID> M_StringToCompactFrameID;
  M_StringToCompactFrameID frameIDs_;
  std::vector<std::string> frameIDs_reverse;
  std::map<CompactFrameID, std::string> frame_authority_;
 
 
  tf2::Duration cache_time_;
 
  typedef std::unordered_map<TransformableCallbackHandle, TransformableCallback> M_TransformableCallback;
  M_TransformableCallback transformable_callbacks_;
  uint32_t transformable_callbacks_counter_;
  std::mutex transformable_callbacks_mutex_;
 
  struct TransformableRequest
  {
    TimePoint time;
    TransformableRequestHandle request_handle;
    TransformableCallbackHandle cb_handle;
    CompactFrameID target_id;
    CompactFrameID source_id;
    std::string target_string;
    std::string source_string;
  };
  typedef std::vector<TransformableRequest> V_TransformableRequest;
  V_TransformableRequest transformable_requests_;
  std::mutex transformable_requests_mutex_;
  uint64_t transformable_requests_counter_;
 
  struct RemoveRequestByCallback;
  struct RemoveRequestByID;
 
 
  /************************* Internal Functions ****************************/
 
  bool setTransformImpl(const tf2::Transform& transform_in, const std::string frame_id,
                        const std::string child_frame_id, const TimePoint stamp,
                        const std::string& authority, bool is_static);
  void lookupTransformImpl(const std::string& target_frame, const std::string& source_frame,
      const TimePoint& time_in, tf2::Transform& transform, TimePoint& time_out) const;
 
  void lookupTransformImpl(const std::string& target_frame, const TimePoint& target_time,
      const std::string& source_frame, const TimePoint& source_time,
      const std::string& fixed_frame, tf2::Transform& transform, TimePoint& time_out) const;
 
  TimeCacheInterfacePtr getFrame(CompactFrameID c_frame_id) const;
 
  TimeCacheInterfacePtr allocateFrame(CompactFrameID cfid, bool is_static);
 
  CompactFrameID validateFrameId(
    const char* function_name_arg,
    const std::string& frame_id,
    std::string* error_msg) const;
 
  CompactFrameID validateFrameId(const char* function_name_arg, const std::string& frame_id) const;
 
  CompactFrameID lookupFrameNumber(const std::string& frameid_str) const;
 
  CompactFrameID lookupOrInsertFrameNumber(const std::string& frameid_str);
 
  const std::string& lookupFrameString(CompactFrameID frame_id_num) const;
 
  void createConnectivityErrorString(CompactFrameID source_frame, CompactFrameID target_frame, std::string* out) const;
 
  tf2::TF2Error getLatestCommonTime(CompactFrameID target_frame, CompactFrameID source_frame, TimePoint& time, std::string* error_string) const;
 
  template<typename F>
  tf2::TF2Error walkToTopParent(F& f, TimePoint time, CompactFrameID target_id, CompactFrameID source_id, std::string* error_string) const;
 
  template<typename F>
  tf2::TF2Error walkToTopParent(F& f, TimePoint time, CompactFrameID target_id, CompactFrameID source_id, std::string* error_string, std::vector<CompactFrameID> *frame_chain) const;
 
  void testTransformableRequests();
  // Thread safe transform check, acquire lock and call canTransformNoLock.
  bool canTransformInternal(CompactFrameID target_id, CompactFrameID source_id,
                    const TimePoint& time, std::string* error_msg) const;
  // Actual implementation to walk the transform tree and find out if a transform exists.
  bool canTransformNoLock(CompactFrameID target_id, CompactFrameID source_id,
                      const TimePoint& time, std::string* error_msg) const;
 
 
  //Whether it is safe to use canTransform with a timeout. (If another thread is not provided it will always timeout.)
  bool using_dedicated_thread_;
 
};
 
 
 
 
}
 
#endif //TF2_CORE_H