Add getKinematicsInfo accessor to PrimaryClient (UniversalRobots#496)

Adds a `getKinematicsInfo()` accessor on `PrimaryClient` that forwards
to the internal `PrimaryConsumer`'s existing accessor. This mirrors the
pattern of `getConfigurationData()`

Also adds the missing mutex around `kinematics_info_` in
`PrimaryConsumer`, matching the synchronization pattern already uses in
every other captures packet member (`robot_mode_`,
`configuration_data_`, `version_information_`, etc). Without it the new
public accessor would expose a data race between the pipeline thread
that writes `kinematics_info_` and the caller thread that reads it.

Author: nfranczak

include/ur_client_library/primary/primary_client.h

@@ -258,6 +258,20 @@ class PrimaryClient
     return consumer_->getConfigurationData();
   }
 
+  /*!
+   * \brief Get the latest kinematics info.
+   *
+   * The kinematics info contains the controller's calibrated DH parameters: the nominal model
+   * combined with the per-arm calibration deltas, plus the calibration checksum/status. It
+   * will be updated in the background. This will always show the latest received kinematics
+   * info independent of the time that has passed since receiving it. If no kinematics info
+   * has been received yet, this will return a nullptr.
+   */
+  std::shared_ptr<KinematicsInfo> getKinematicsInfo()
+  {
+    return consumer_->getKinematicsInfo();
+  }
+
   /*!
    * \brief Get the Robot type
    *

include/ur_client_library/primary/primary_consumer.h

@@ -107,6 +107,7 @@ class PrimaryConsumer : public AbstractPrimaryConsumer
   virtual bool consume(KinematicsInfo& pkg) override
   {
     URCL_LOG_DEBUG("%s", pkg.toString().c_str());
+    std::scoped_lock lock(kinematics_info_mutex_);
     kinematics_info_ = std::make_shared<KinematicsInfo>(pkg);
     return true;
   }
@@ -203,6 +204,7 @@ class PrimaryConsumer : public AbstractPrimaryConsumer
    */
   std::shared_ptr<KinematicsInfo> getKinematicsInfo()
   {
+    std::scoped_lock lock(kinematics_info_mutex_);
     return kinematics_info_;
   }
 
@@ -259,6 +261,7 @@ class PrimaryConsumer : public AbstractPrimaryConsumer
 private:
   std::function<void(ErrorCode&)> error_code_message_callback_;
   std::shared_ptr<KinematicsInfo> kinematics_info_;
+  std::mutex kinematics_info_mutex_;
   std::mutex robot_mode_mutex_;
   std::shared_ptr<RobotModeData> robot_mode_;
   std::mutex version_information_mutex_;

tests/test_primary_client.cpp

@@ -268,6 +268,24 @@ TEST_F(PrimaryClientTest, test_configuration_data)
   EXPECT_NE(client_->getRobotType(), RobotType::UNDEFINED);
 }
 
+TEST_F(PrimaryClientTest, test_kinematics_info)
+{
+  EXPECT_NO_THROW(client_->start());
+
+  // Once we connect to the primary client we should receive kinematics info
+  auto start_time = std::chrono::system_clock::now();
+  const auto timeout = std::chrono::seconds(1);
+  auto kinematics_info = client_->getKinematicsInfo();
+  while (kinematics_info == nullptr && std::chrono::system_clock::now() - start_time < timeout)
+  {
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    kinematics_info = client_->getKinematicsInfo();
+  }
+
+  // We should have received a kinematics info package
+  EXPECT_NE(kinematics_info, nullptr);
+}
+
 TEST_F(PrimaryClientTest, test_get_robot_series)
 {
   EXPECT_NO_THROW(client_->start());