buffer_core.h

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// Copyright 2008, Willow Garage, Inc. All rights reserved.
//
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// modification, are permitted provided that the following conditions are met:
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//    * Neither the name of the {copyright_holder} nor the names of its
//      contributors may be used to endorse or promote products derived from
//      this software without specific prior written permission.
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#ifndef TF2__BUFFER_CORE_H_
#define TF2__BUFFER_CORE_H_
 
#include <algorithm>
#include <cmath>
#include <functional>
#include <map>
#include <memory>
#include <mutex>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
 
#include "LinearMath/Transform.h"
#include "geometry_msgs/msg/transform_stamped.hpp"
#include "tf2/buffer_core_interface.h"
#include "tf2/exceptions.h"
#include "tf2/transform_storage.h"
#include "tf2/visibility_control.h"
 
namespace tf2
{
 
typedef std::pair<TimePoint, CompactFrameID> P_TimeAndFrameID;
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
  explicit 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;
 
  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
  TransformableRequestHandle addTransformableRequest(
    const TransformableCallback & cb,
    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 uint32_t TransformableCallbackHandle;
 
  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_;
 
 
  /************************* 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_;
};
}  // namespace tf2
 
#endif  // TF2__BUFFER_CORE_H_