[wpilib] PWMSpeedController: Use PWM by composition (#3248)

This cleans up the user experience by removing lower-level functions from the
interface.

Also remove MotorSafety from "raw" PWM.

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

@@ -5,11 +5,14 @@
 #pragma once
 
 #include <wpi/mutex.h>
-#include <wpi/raw_ostream.h>
 
 #include "frc/ErrorBase.h"
 #include "frc/Timer.h"
 
+namespace wpi {
+class raw_ostream;
+}  // namespace wpi
+
 namespace frc {
 
 /**

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

@@ -7,9 +7,8 @@
 #include <stdint.h>
 
 #include <hal/Types.h>
-#include <wpi/raw_ostream.h>
 
-#include "frc/MotorSafety.h"
+#include "frc/ErrorBase.h"
 #include "frc/smartdashboard/Sendable.h"
 #include "frc/smartdashboard/SendableHelper.h"
 
@@ -34,7 +33,7 @@ class SendableBuilder;
  *   - 1 = minimum pulse width (currently 0.5ms)
  *   - 0 = disabled (i.e. PWM output is held low)
  */
-class PWM : public MotorSafety, public Sendable, public SendableHelper<PWM> {
+class PWM : public ErrorBase, public Sendable, public SendableHelper<PWM> {
  public:
   friend class AddressableLED;
   /**
@@ -64,8 +63,10 @@ class PWM : public MotorSafety, public Sendable, public SendableHelper<PWM> {
    *
    * @param channel The PWM channel number. 0-9 are on-board, 10-19 are on the
    *                MXP port
+   * @param registerSendable If true, adds this instance to SendableRegistry
+   *                         and LiveWindow
    */
-  explicit PWM(int channel);
+  explicit PWM(int channel, bool registerSendable = true);
 
   /**
    * Free the PWM channel.
@@ -77,10 +78,6 @@ class PWM : public MotorSafety, public Sendable, public SendableHelper<PWM> {
   PWM(PWM&&) = default;
   PWM& operator=(PWM&&) = default;
 
-  // MotorSafety interface
-  void StopMotor() override;
-  void GetDescription(wpi::raw_ostream& desc) const override;
-
   /**
    * Set the PWM value directly to the hardware.
    *

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

@@ -4,15 +4,27 @@
 
 #pragma once
 
+#include <wpi/Twine.h>
+
+#include "frc/MotorSafety.h"
 #include "frc/PWM.h"
 #include "frc/SpeedController.h"
+#include "frc/smartdashboard/Sendable.h"
+#include "frc/smartdashboard/SendableHelper.h"
+
+namespace wpi {
+class raw_ostream;
+}  // namespace wpi
 
 namespace frc {
 
 /**
  * Common base class for all PWM Speed Controllers.
  */
-class PWMSpeedController : public PWM, public SpeedController {
+class PWMSpeedController : public SpeedController,
+                           public MotorSafety,
+                           public Sendable,
+                           public SendableHelper<PWMSpeedController> {
  public:
   PWMSpeedController(PWMSpeedController&&) = default;
   PWMSpeedController& operator=(PWMSpeedController&&) = default;
@@ -42,7 +54,11 @@ class PWMSpeedController : public PWM, public SpeedController {
 
   void Disable() override;
 
+  // MotorSafety interface
   void StopMotor() override;
+  void GetDescription(wpi::raw_ostream& desc) const override;
+
+  int GetChannel() const;
 
   /**
    * Write out the PID value as seen in the PIDOutput base object.
@@ -55,13 +71,16 @@ class PWMSpeedController : public PWM, public SpeedController {
   /**
    * Constructor for a PWM Speed Controller connected via PWM.
    *
+   * @param name Name to use for SendableRegistry
    * @param channel The PWM channel that the controller is attached to. 0-9 are
    *                on-board, 10-19 are on the MXP port
    */
-  explicit PWMSpeedController(int channel);
+  PWMSpeedController(const wpi::Twine& name, int channel);
 
   void InitSendable(SendableBuilder& builder) override;
 
+  PWM m_pwm;
+
  private:
   bool m_isInverted = false;
 };