PerpetualCommand.h

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// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
 
#pragma once
 
#ifdef _WIN32
#pragma warning(push)
#pragma warning(disable : 4521)
#endif
 
#include <memory>
#include <utility>
 
#include "frc2/command/CommandBase.h"
#include "frc2/command/CommandHelper.h"
 
namespace frc2 {
/**
 * A command that runs another command in perpetuity, ignoring that command's
 * end conditions.  While this class does not extend frc2::CommandGroupBase,
 * it is still considered a CommandGroup, as it allows one to compose another
 * command within it; the command instances that are passed to it cannot be
 * added to any other groups, or scheduled individually.
 *
 * <p>As a rule, CommandGroups require the union of the requirements of their
 * component commands.
 *
 * This class is provided by the NewCommands VendorDep
 *
 * @deprecated PerpetualCommand violates the assumption that execute() doesn't
get called after isFinished() returns true -- an assumption that should be
valid. This was unsafe/undefined behavior from the start, and RepeatCommand
provides an easy way to achieve similar end results with slightly different (and
safe) semantics.
 */
class PerpetualCommand : public CommandHelper<CommandBase, PerpetualCommand> {
 public:
  /**
   * Creates a new PerpetualCommand.  Will run another command in perpetuity,
   * ignoring that command's end conditions, unless this command itself is
   * interrupted.
   *
   * @param command the command to run perpetually
   */
  WPI_DEPRECATED(
      "PerpetualCommand violates the assumption that execute() doesn't get "
      "called after isFinished() returns true -- an assumption that should be "
      "valid."
      "This was unsafe/undefined behavior from the start, and RepeatCommand "
      "provides an easy way to achieve similar end results with slightly "
      "different (and safe) semantics.")
  explicit PerpetualCommand(std::unique_ptr<Command>&& command);
  WPI_IGNORE_DEPRECATED
 
  /**
   * Creates a new PerpetualCommand.  Will run another command in perpetuity,
   * ignoring that command's end conditions, unless this command itself is
   * interrupted.
   *
   * @param command the command to run perpetually
   */
  template <class T, typename = std::enable_if_t<std::is_base_of_v<
                         Command, std::remove_reference_t<T>>>>
  WPI_DEPRECATED(
      "PerpetualCommand violates the assumption that execute() doesn't get "
      "called after isFinished() returns true -- an assumption that should be "
      "valid."
      "This was unsafe/undefined behavior from the start, and RepeatCommand "
      "provides an easy way to achieve similar end results with slightly "
      "different (and safe) semantics.")
  explicit PerpetualCommand(T&& command)
      : PerpetualCommand(std::make_unique<std::remove_reference_t<T>>(
            std::forward<T>(command))) {}
  WPI_UNIGNORE_DEPRECATED
 
  PerpetualCommand(PerpetualCommand&& other) = default;
 
  // No copy constructors for command groups
  PerpetualCommand(const PerpetualCommand& other) = delete;
 
  // Prevent template expansion from emulating copy ctor
  PerpetualCommand(PerpetualCommand&) = delete;
 
  void Initialize() override;
 
  void Execute() override;
 
  void End(bool interrupted) override;
 
 private:
  std::unique_ptr<Command> m_command;
};
}  // namespace frc2
 
#ifdef _WIN32
#pragma warning(pop)
#endif