Remove PIDControllerRunner and mutex from new PIDController (#1795)

Teams that wish to use it asynchronously may still do so - they simply need to handle the thread safety themselves (it is not that difficult, and can be done more cleanly in the calling code anyway).

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

@@ -10,8 +10,6 @@
 #include <functional>
 #include <limits>
 
-#include <wpi/mutex.h>
-
 #include "frc/smartdashboard/SendableBase.h"
 
 namespace frc2 {
@@ -36,8 +34,10 @@ class PIDController : public frc::SendableBase {
 
   ~PIDController() override = default;
 
-  PIDController(PIDController&& rhs);
-  PIDController& operator=(PIDController&& rhs);
+  PIDController(const PIDController&) = default;
+  PIDController& operator=(const PIDController&) = default;
+  PIDController(PIDController&&) = default;
+  PIDController& operator=(PIDController&&) = default;
 
   /**
    * Sets the PID Controller gain parameters.
@@ -233,11 +233,9 @@ class PIDController : public frc::SendableBase {
   void InitSendable(frc::SendableBuilder& builder) override;
 
  protected:
-  mutable wpi::mutex m_thisMutex;
-
   /**
    * Wraps error around for continuous inputs. The original error is returned if
-   * continuous mode is disabled. This is an unsynchronized function.
+   * continuous mode is disabled.
    *
    * @param error The current error of the PID controller.
    * @return Error for continuous inputs.
@@ -293,15 +291,6 @@ class PIDController : public frc::SendableBase {
 
   double m_setpoint = 0;
   double m_output = 0;
-
-  /**
-   * Returns the next output of the PID controller.
-   *
-   * Unlike the public functions above, this function doesn't lock the mutex.
-   *
-   * @param measurement The current measurement of the process variable.
-   */
-  double CalculateUnsafe(double measurement);
 };
 
 }  // namespace frc2

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

@@ -1,78 +0,0 @@
-/*----------------------------------------------------------------------------*/
-/* Copyright (c) 2018-2019 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.                                                               */
-/*----------------------------------------------------------------------------*/
-
-#pragma once
-
-#include <functional>
-
-#include <wpi/mutex.h>
-
-#include "frc/Notifier.h"
-#include "frc/controller/PIDController.h"
-#include "frc/smartdashboard/SendableBase.h"
-
-namespace frc {
-
-class PIDControllerRunner : SendableBase {
- public:
-  /**
-   * Allocates a PIDControllerRunner.
-   *
-   * @param controller       The controller on which to call Update().
-   * @param controllerOutput The function which updates the plant using the
-   *                         controller output passed as the argument.
-   */
-  PIDControllerRunner(frc2::PIDController& controller,
-                      std::function<double(void)> measurementSource,
-                      std::function<void(double)> controllerOutput);
-
-  ~PIDControllerRunner();
-
-  PIDControllerRunner(PIDControllerRunner&&) = default;
-  PIDControllerRunner& operator=(PIDControllerRunner&&) = default;
-
-  /**
-   * Begins running the controller.
-   */
-  void Enable();
-
-  /**
-   * Stops running the controller.
-   *
-   * This sets the output to zero before stopping.
-   */
-  void Disable();
-
-  /**
-   * Returns whether controller is running.
-   */
-  bool IsEnabled() const;
-
-  void InitSendable(SendableBuilder& builder) override;
-
- private:
-  frc2::PIDController& m_controller;
-  std::function<double(void)> m_measurementSource;
-  std::function<void(double)> m_controllerOutput;
-  bool m_enabled = false;
-
-  mutable wpi::mutex m_thisMutex;
-
-  // Ensures when Disable() is called, m_controllerOutput() won't run if
-  // Controller::Update() is already running at that time.
-  mutable wpi::mutex m_outputMutex;
-
-  // This is declared after all other member variables so that during
-  // PIDControllerRunner destruction, the Notifier is stopped before any member
-  // variables its callable uses are destructed. This avoids use-after-free
-  // bugs like crashes when locking is attempted on deallocated mutexes.
-  Notifier m_notifier{&PIDControllerRunner::Run, this};
-
-  void Run();
-};
-
-}  // namespace frc