wpilibc: Add overloads for units (#1815)

Add unit-taking overloads to the following classes:
- IterativeRobotBase
- LinearFilter
- Notifier
- TimedRobot
- Timer (HasPeriodPassed only)
- frc2::PIDController

The corresponding non-units-taking functions have been deprecated.

The return value of TimedRobot::GetPeriod() was updated.
This is a breaking change, users should use to<double> to get the value in seconds.

Other return values, e.g. Timer::Get(), have NOT been updated due to much wider use.

wpilibc/src/main/native/include/frc/IterativeRobotBase.h

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2017-2018 FIRST. All Rights Reserved.                        */
+/* Copyright (c) 2017-2019 FIRST. All Rights Reserved.                        */
 /* Open Source Software - may be modified and shared by FRC teams. The code   */
 /* must be accompanied by the FIRST BSD license file in the root directory of */
 /* the project.                                                               */
@@ -7,6 +7,9 @@
 
 #pragma once
 
+#include <units/units.h>
+#include <wpi/deprecated.h>
+
 #include "frc/RobotBase.h"
 #include "frc/Watchdog.h"
 
@@ -141,8 +144,16 @@ class IterativeRobotBase : public RobotBase {
    *
    * @param period Period in seconds.
    */
+  WPI_DEPRECATED("Use ctor with unit-safety instead.")
   explicit IterativeRobotBase(double period);
 
+  /**
+   * Constructor for IterativeRobotBase.
+   *
+   * @param period Period.
+   */
+  explicit IterativeRobotBase(units::second_t period);
+
   virtual ~IterativeRobotBase() = default;
 
   IterativeRobotBase(IterativeRobotBase&&) = default;

wpilibc/src/main/native/include/frc/LinearFilter.h

@@ -10,6 +10,7 @@
 #include <initializer_list>
 #include <vector>
 
+#include <units/units.h>
 #include <wpi/ArrayRef.h>
 
 #include "frc/circular_buffer.h"
@@ -99,7 +100,8 @@ class LinearFilter {
    * @param period       The period in seconds between samples taken by the
    *                     user.
    */
-  static LinearFilter SinglePoleIIR(double timeConstant, double period);
+  static LinearFilter SinglePoleIIR(double timeConstant,
+                                    units::second_t period);
 
   /**
    * Creates a first-order high-pass filter of the form:<br>
@@ -112,7 +114,7 @@ class LinearFilter {
    * @param period       The period in seconds between samples taken by the
    *                     user.
    */
-  static LinearFilter HighPass(double timeConstant, double period);
+  static LinearFilter HighPass(double timeConstant, units::second_t period);
 
   /**
    * Creates a K-tap FIR moving average filter of the form:<br>

wpilibc/src/main/native/include/frc/Notifier.h

@@ -15,6 +15,8 @@
 #include <utility>
 
 #include <hal/Types.h>
+#include <units/units.h>
+#include <wpi/deprecated.h>
 #include <wpi/mutex.h>
 
 #include "frc/ErrorBase.h"
@@ -58,8 +60,18 @@ class Notifier : public ErrorBase {
    *
    * @param delay Seconds to wait before the handler is called.
    */
+  WPI_DEPRECATED("Use unit-safe StartSingle method instead.")
   void StartSingle(double delay);
 
+  /**
+   * Register for single event notification.
+   *
+   * A timer event is queued for a single event after the specified delay.
+   *
+   * @param delay Amount of time to wait before the handler is called.
+   */
+  void StartSingle(units::second_t delay);
+
   /**
    * Register for periodic event notification.
    *
@@ -70,8 +82,21 @@ class Notifier : public ErrorBase {
    * @param period Period in seconds to call the handler starting one period
    *               after the call to this method.
    */
+  WPI_DEPRECATED("Use unit-safe StartPeriodic method instead.")
   void StartPeriodic(double period);
 
+  /**
+   * Register for periodic event notification.
+   *
+   * A timer event is queued for periodic event notification. Each time the
+   * interrupt occurs, the event will be immediately requeued for the same time
+   * interval.
+   *
+   * @param period Period to call the handler starting one period
+   *               after the call to this method.
+   */
+  void StartPeriodic(units::second_t period);
+
   /**
    * Stop timer events from occuring.
    *

wpilibc/src/main/native/include/frc/TimedRobot.h

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2017-2018 FIRST. All Rights Reserved.                        */
+/* Copyright (c) 2017-2019 FIRST. All Rights Reserved.                        */
 /* Open Source Software - may be modified and shared by FRC teams. The code   */
 /* must be accompanied by the FIRST BSD license file in the root directory of */
 /* the project.                                                               */
@@ -8,6 +8,8 @@
 #pragma once
 
 #include <hal/Types.h>
+#include <units/units.h>
+#include <wpi/deprecated.h>
 
 #include "frc/ErrorBase.h"
 #include "frc/IterativeRobotBase.h"
@@ -25,7 +27,7 @@ namespace frc {
  */
 class TimedRobot : public IterativeRobotBase, public ErrorBase {
  public:
-  static constexpr double kDefaultPeriod = 0.02;
+  static constexpr units::second_t kDefaultPeriod = 20_ms;
 
   /**
    * Provide an alternate "main loop" via StartCompetition().
@@ -35,14 +37,22 @@ class TimedRobot : public IterativeRobotBase, public ErrorBase {
   /**
    * Get the time period between calls to Periodic() functions.
    */
-  double GetPeriod() const;
+  units::second_t GetPeriod() const;
 
   /**
    * Constructor for TimedRobot.
    *
    * @param period Period in seconds.
    */
-  explicit TimedRobot(double period = kDefaultPeriod);
+  WPI_DEPRECATED("Use constructor with unit-safety instead.")
+  explicit TimedRobot(double period);
+
+  /**
+   * Constructor for TimedRobot.
+   *
+   * @param period Period.
+   */
+  explicit TimedRobot(units::second_t period = kDefaultPeriod);
 
   ~TimedRobot() override;
 

wpilibc/src/main/native/include/frc/Timer.h

@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <units/units.h>
 #include <wpi/deprecated.h>
 #include <wpi/mutex.h>
 
@@ -101,8 +102,19 @@ class Timer {
    * @param period The period to check for (in seconds).
    * @return       True if the period has passed.
    */
+  WPI_DEPRECATED("Use unit-safe HasPeriodPassed method instead.")
   bool HasPeriodPassed(double period);
 
+  /**
+   * Check if the period specified has passed and if it has, advance the start
+   * time by that period. This is useful to decide if it's time to do periodic
+   * work without drifting later by the time it took to get around to checking.
+   *
+   * @param period The period to check for.
+   * @return       True if the period has passed.
+   */
+  bool HasPeriodPassed(units::second_t period);
+
   /**
    * Return the FPGA system clock time in seconds.
    *

wpilibc/src/main/native/include/frc/controller/PIDController.h

@@ -10,6 +10,8 @@
 #include <functional>
 #include <limits>
 
+#include <units/units.h>
+
 #include "frc/smartdashboard/SendableBase.h"
 
 namespace frc2 {
@@ -30,7 +32,8 @@ class PIDController : public frc::SendableBase {
    * @param period The period between controller updates in seconds. The
    *               default is 0.02 seconds.
    */
-  PIDController(double Kp, double Ki, double Kd, double period = 0.02);
+  PIDController(double Kp, double Ki, double Kd,
+                units::second_t period = 20_ms);
 
   ~PIDController() override = default;
 
@@ -97,7 +100,7 @@ class PIDController : public frc::SendableBase {
    *
    * @return The period of the controller.
    */
-  double GetPeriod() const;
+  units::second_t GetPeriod() const;
 
   /**
    * Returns the current controller output.