Add public API to get player's starting time and playback duration (#2095)

* Bring getters for starting time and duration on rosbag2_transport layer

Signed-off-by: Michael Orlov <[email protected]>

* Bring getters for starting time and duration on rosbag2_py layer

Signed-off-by: Michael Orlov <[email protected]>

* Regenerate Python stub files (.pyi)

Signed-off-by: Michael Orlov <[email protected]>

---------

Signed-off-by: Michael Orlov <[email protected]>

Author: MichaelOrlov

rosbag2_py/rosbag2_py/_transport.pyi

@@ -72,6 +72,8 @@ class Player:
     def burst(self, num_messages) -> Any: ...
     @staticmethod
     def cancel() -> None: ...
+    def get_playback_duration(self) -> int: ...
+    def get_starting_time(self) -> int: ...
     def is_paused(self) -> bool: ...
     def pause(self) -> None: ...
     @overload

rosbag2_py/src/rosbag2_py/_transport.cpp

@@ -311,7 +311,7 @@ class Player
     player_->resume();
   }
 
-  bool is_paused() const
+  [[nodiscard]] bool is_paused() const
   {
     if (!player_) {
       throw std::runtime_error("Player is not initialized. Please use constructor with "
@@ -320,6 +320,24 @@ class Player
     return player_->is_paused();
   }
 
+  [[nodiscard]] int64_t get_starting_time() const
+  {
+    if (!player_) {
+      throw std::runtime_error("Player is not initialized. Please use constructor with "
+        "storage and play options.");
+    }
+    return player_->get_starting_time();
+  }
+
+  [[nodiscard]] int64_t get_playback_duration() const
+  {
+    if (!player_) {
+      throw std::runtime_error("Player is not initialized. Please use constructor with "
+        "storage and play options.");
+    }
+    return player_->get_playback_duration();
+  }
+
   bool play_next()
   {
     if (!player_) {
@@ -1070,6 +1088,24 @@ PYBIND11_MODULE(_transport, m) {
     &rosbag2_py::Player::is_paused,
     "Whether the playback is currently paused.")
 
+  .def("get_starting_time",
+    &rosbag2_py::Player::get_starting_time,
+    R"pbdoc(
+      Get the starting time of the playback.
+
+      Returns:
+          int: The timestamp of the first message in nanoseconds.
+    )pbdoc")
+
+  .def("get_playback_duration",
+    &rosbag2_py::Player::get_playback_duration,
+    R"pbdoc(
+      Get the total duration of the playback.
+
+      Returns:
+          int: The total duration of the playback in nanoseconds.
+    )pbdoc")
+
   .def("play_next", &rosbag2_py::Player::play_next,
     R"pbdoc(
       Playing next message from queue when in pause.

rosbag2_py/test/test_transport.py

@@ -148,6 +148,36 @@ def test_player_api(storage_id):
     ctx.shutdown()
 
 
+@pytest.mark.parametrize('storage_id', TESTED_STORAGE_IDS)
+def test_player_get_starting_time(storage_id):
+    bag_path = str(RESOURCES_PATH / storage_id / 'talker')
+    assert os.path.exists(bag_path), 'Could not find test bag file: ' + bag_path
+
+    storage_options, _ = get_rosbag_options(bag_path, storage_id)
+
+    play_options = rosbag2_py.PlayOptions()
+    play_options.topics_to_filter = ['topic']
+
+    player = rosbag2_py.Player(storage_options, play_options, 'info', 'rosbag2_player_test')
+    starting_time = player.get_starting_time()
+    assert starting_time is not None, 'Expected a valid starting time'
+
+
+@pytest.mark.parametrize('storage_id', TESTED_STORAGE_IDS)
+def test_player_get_playback_duration(storage_id):
+    bag_path = str(RESOURCES_PATH / storage_id / 'talker')
+    assert os.path.exists(bag_path), 'Could not find test bag file: ' + bag_path
+
+    storage_options, _ = get_rosbag_options(bag_path, storage_id)
+
+    play_options = rosbag2_py.PlayOptions()
+    play_options.topics_to_filter = ['topic']
+
+    player = rosbag2_py.Player(storage_options, play_options, 'info', 'rosbag2_player_test')
+    playback_duration = player.get_playback_duration()
+    assert playback_duration is not None, 'Expected a valid starting time'
+
+
 @pytest.mark.parametrize('storage_id', TESTED_STORAGE_IDS)
 def test_recorder_api(tmp_path, storage_id):
     bag_path = tmp_path / 'test_recorder_api'

rosbag2_transport/include/rosbag2_transport/player.hpp

@@ -252,6 +252,16 @@ class Player : public rclcpp::Node
   ROSBAG2_TRANSPORT_PUBLIC
   bool is_paused() const;
 
+  /// \brief Getter method for starting time of the playback.
+  /// \return Returns timestamp of the first message in nanoseconds.
+  ROSBAG2_TRANSPORT_PUBLIC
+  rcutils_time_point_value_t get_starting_time() const;
+
+  /// \brief Getter method for playback duration
+  /// \return Returns duration of the playback in nanoseconds.
+  ROSBAG2_TRANSPORT_PUBLIC
+  rcutils_duration_value_t get_playback_duration() const;
+
   /// Return current playback rate.
   ROSBAG2_TRANSPORT_PUBLIC
   double get_rate() const;

rosbag2_transport/src/rosbag2_transport/player.cpp

@@ -120,6 +120,14 @@ class PlayerImpl
   /// Return whether the playback is currently paused.
   bool is_paused() const;
 
+  /// \brief Getter method for starting time of the playback.
+  /// \return Returns timestamp of the first message in nanoseconds.
+  rcutils_time_point_value_t get_starting_time() const;
+
+  /// \brief Getter method for playback duration
+  /// \return Returns duration of the playback in nanoseconds.
+  rcutils_duration_value_t get_playback_duration() const;
+
   /// Return current playback rate.
   double get_rate() const;
 
@@ -380,7 +388,8 @@ class PlayerImpl
   // Whether we successfully played next
   std::atomic_bool play_next_result_{false};
 
-  rcutils_time_point_value_t starting_time_;
+  rcutils_time_point_value_t starting_time_ = 0;
+  rcutils_duration_value_t playback_duration_ = 0;
 
   // control services
   rclcpp::Service<rosbag2_interfaces::srv::Pause>::SharedPtr srv_pause_;
@@ -524,6 +533,8 @@ PlayerImpl::PlayerImpl(
       starting_time_ += play_options_.start_offset;
     }
 
+    playback_duration_ = ending_time - starting_time_;
+
     progress_bar_ = std::make_unique<PlayerProgressBar>(
       std::cout, starting_time_, ending_time,
       play_options.progress_bar_update_rate,
@@ -782,6 +793,16 @@ bool PlayerImpl::is_paused() const
   return clock_->is_paused();
 }
 
+rcutils_time_point_value_t PlayerImpl::get_starting_time() const
+{
+  return starting_time_;
+}
+
+rcutils_duration_value_t PlayerImpl::get_playback_duration() const
+{
+  return playback_duration_;
+}
+
 double PlayerImpl::get_rate() const
 {
   return clock_->get_rate();
@@ -2274,6 +2295,16 @@ bool Player::is_paused() const
   return pimpl_->is_paused();
 }
 
+rcutils_time_point_value_t Player::get_starting_time() const
+{
+  return pimpl_->get_starting_time();
+}
+
+rcutils_duration_value_t Player::get_playback_duration() const
+{
+  return pimpl_->get_playback_duration();
+}
+
 double Player::get_rate() const
 {
   return pimpl_->get_rate();

rosbag2_transport/test/rosbag2_transport/mock_sequential_reader.hpp

@@ -142,6 +142,10 @@ class MockSequentialReader : public rosbag2_cpp::reader_interfaces::BaseReaderIn
         std::chrono::nanoseconds(messages[0]->recv_timestamp));
       metadata_.starting_time = message_timestamp;
     }
+    metadata_.duration = std::chrono::nanoseconds(messages.back()->recv_timestamp -
+      std::chrono::duration_cast<std::chrono::nanoseconds>(
+        metadata_.starting_time.time_since_epoch()).count());
+
     messages_ = std::move(messages);
     topics_ = std::move(topics);
   }

rosbag2_transport/test/rosbag2_transport/test_play_timing.cpp

@@ -56,9 +56,12 @@ class PlayerTestFixture : public Rosbag2TransportTestFixture
       serialize_test_message("topic1", 0, primitive_message2)
     };
 
-    messages[0]->recv_timestamp = 100;
+    messages[0]->send_timestamp = 80;
+    messages[0]->recv_timestamp = 90;
     messages[1]->recv_timestamp = messages[0]->recv_timestamp +
       message_time_difference.nanoseconds();
+    messages[1]->send_timestamp = messages[0]->send_timestamp +
+      message_time_difference.nanoseconds();
 
     prepared_mock_reader = std::make_unique<MockSequentialReader>();
     prepared_mock_reader->prepare(messages, topics_and_types);
@@ -78,6 +81,28 @@ class PlayerTestFixture : public Rosbag2TransportTestFixture
   std::unique_ptr<rosbag2_cpp::Reader> reader;
 };
 
+TEST_F(PlayerTestFixture, get_starting_time_returns_correct_value)
+{
+  auto player = std::make_shared<rosbag2_transport::Player>(
+    std::move(reader), storage_options_, play_options_);
+
+  rcutils_time_point_value_t starting_time = player->get_starting_time();
+  // The starting time is the time of the first message in the bag
+  EXPECT_EQ(starting_time, messages[0]->recv_timestamp);
+}
+
+TEST_F(PlayerTestFixture, get_playback_duration_returns_correct_value)
+{
+  auto player = std::make_shared<rosbag2_transport::Player>(
+    std::move(reader), storage_options_, play_options_);
+
+  auto playback_duration = player->get_playback_duration();
+  // The playback duration is the time difference between the first and last message in the bag
+  rcutils_duration_value_t expected_duration =
+    messages.back()->recv_timestamp - messages[0]->recv_timestamp;
+  EXPECT_EQ(playback_duration, expected_duration);
+}
+
 TEST_F(PlayerTestFixture, playing_respects_relative_timing_of_stored_messages)
 {
   auto player = std::make_shared<rosbag2_transport::Player>(