Use rcl_time_point_valid

Signed-off-by: methylDragon <methylDragon@gmail.com>

rclcpp/include/rclcpp/clock.hpp

@@ -145,13 +145,8 @@ class Clock
    * uninitialized time (i.e. with zero time.)
    *
    * Note:
-   *     This notion of validity is different from the rcl notion of validity (rcl_clock_valid)!
-   *     A clock that is rcl_clock_valid is a clock that can be used to get a time (i.e. not
-   *     NULL, not RCL_CLOCK_UNINITIALIZED, or with a missing get_now() method.)
-   *
-   *     A clock that is valid in the sense codified by this method is a clock with non-zero time.
-   *     Consequently, a clock that is not rcl_clock_valid can never become valid, since it cannot
-   *     be used to obtain a time.
+   *     A valid clock must be both rcl_clock_valid and hold a time that is rcl_time_point_valid.
+   *     An invalid clock can potentially become valid if it is rcl_clock_valid.
    *
    * \return true if clock was or became valid
    */

rclcpp/include/rclcpp/time.hpp

@@ -210,6 +210,16 @@ class Time
   rcl_clock_type_t
   get_clock_type() const;
 
+  /// Check if time is valid.
+  /**
+   * A valid time is a time that is non-zero.
+   *
+   * \return true if the time is valid
+   */
+  RCLCPP_PUBLIC
+  bool
+  is_valid() const;
+
 private:
   rcl_time_point_t rcl_time_;
   friend Clock;  // Allow clock to manipulate internal data

rclcpp/src/rclcpp/clock.cpp

@@ -195,7 +195,7 @@ Clock::is_valid()
     case RCL_ROS_TIME:
     case RCL_STEADY_TIME:
     case RCL_SYSTEM_TIME:
-      return now().nanoseconds() > 0;
+      return now().is_valid();
 
     // By right we shouldn't even get to this block, but these cases are included for completeness
     case RCL_CLOCK_UNINITIALIZED:

rclcpp/src/rclcpp/time.cpp

@@ -233,6 +233,12 @@ Time::get_clock_type() const
   return rcl_time_.clock_type;
 }
 
+bool
+Time::is_valid() const
+{
+  return rcl_time_point_valid(const_cast<rcl_time_point_t *>(&rcl_time_));
+}
+
 Time
 operator+(const rclcpp::Duration & lhs, const rclcpp::Time & rhs)
 {

rclcpp/test/rclcpp/test_time.cpp

@@ -452,6 +452,18 @@ TEST_F(TestTime, test_overflow_underflow_throws) {
     std::underflow_error("addition leads to int64_t underflow"));
 }
 
+TEST_F(TestTime, validity) {
+  EXPECT_FALSE(rclcpp::Time(0, 0, RCL_CLOCK_UNINITIALIZED).is_valid());
+  EXPECT_FALSE(rclcpp::Time(0, 0, RCL_SYSTEM_TIME).is_valid());
+  EXPECT_FALSE(rclcpp::Time(0, 0, RCL_STEADY_TIME).is_valid());
+  EXPECT_FALSE(rclcpp::Time(0, 0, RCL_ROS_TIME).is_valid());
+
+  EXPECT_TRUE(rclcpp::Time(0, 1, RCL_CLOCK_UNINITIALIZED).is_valid());
+  EXPECT_TRUE(rclcpp::Time(0, 1, RCL_SYSTEM_TIME).is_valid());
+  EXPECT_TRUE(rclcpp::Time(0, 1, RCL_STEADY_TIME).is_valid());
+  EXPECT_TRUE(rclcpp::Time(0, 1, RCL_ROS_TIME).is_valid());
+}
+
 class TestClockSleep : public ::testing::Test
 {
 protected: