Renamed folders for consistency, using sim/athena/shared schema (#27)

Rename the following folders:
hal/lib/Athena -> hal/lib/athena
hal/lib/Desktop -> hal/lib/sim
hal/lib/Shared -> hal/lib/shared
wpilibc/Athena -> wpilibc/athena
wpilibc/simulation -> wpilibc/sim

Windows users may need to run gradlew clean after updating.

wpilibc/sim/src/MotorSafetyHelper.cpp

@@ -0,0 +1,145 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008-2016. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "MotorSafetyHelper.h"
+
+#include "DriverStation.h"
+#include "MotorSafety.h"
+#include "Timer.h"
+#include "WPIErrors.h"
+
+#include <stdio.h>
+#include <sstream>
+
+std::set<MotorSafetyHelper*> MotorSafetyHelper::m_helperList;
+priority_recursive_mutex MotorSafetyHelper::m_listMutex;
+
+/**
+ * The constructor for a MotorSafetyHelper object.
+ *
+ * The helper object is constructed for every object that wants to implement the
+ * Motor Safety protocol. The helper object has the code to actually do the
+ * timing and call the motors Stop() method when the timeout expires. The motor
+ * object is expected to call the Feed() method whenever the motors value is
+ * updated.
+ *
+ * @param safeObject a pointer to the motor object implementing MotorSafety.
+ *                   This is used to call the Stop() method on the motor.
+ */
+MotorSafetyHelper::MotorSafetyHelper(MotorSafety* safeObject)
+    : m_safeObject(safeObject) {
+  m_enabled = false;
+  m_expiration = DEFAULT_SAFETY_EXPIRATION;
+  m_stopTime = Timer::GetFPGATimestamp();
+
+  std::lock_guard<priority_recursive_mutex> sync(m_listMutex);
+  m_helperList.insert(this);
+}
+
+MotorSafetyHelper::~MotorSafetyHelper() {
+  std::lock_guard<priority_recursive_mutex> sync(m_listMutex);
+  m_helperList.erase(this);
+}
+
+/**
+ * Feed the motor safety object.
+ *
+ * Resets the timer on this object that is used to do the timeouts.
+ */
+void MotorSafetyHelper::Feed() {
+  std::lock_guard<priority_recursive_mutex> sync(m_syncMutex);
+  m_stopTime = Timer::GetFPGATimestamp() + m_expiration;
+}
+
+/**
+ * Set the expiration time for the corresponding motor safety object.
+ *
+ * @param expirationTime The timeout value in seconds.
+ */
+void MotorSafetyHelper::SetExpiration(float expirationTime) {
+  std::lock_guard<priority_recursive_mutex> sync(m_syncMutex);
+  m_expiration = expirationTime;
+}
+
+/**
+ * Retrieve the timeout value for the corresponding motor safety object.
+ *
+ * @return the timeout value in seconds.
+ */
+float MotorSafetyHelper::GetExpiration() const {
+  std::lock_guard<priority_recursive_mutex> sync(m_syncMutex);
+  return m_expiration;
+}
+
+/**
+ * Determine if the motor is still operating or has timed out.
+ *
+ * @return a true value if the motor is still operating normally and hasn't
+ *         timed out.
+ */
+bool MotorSafetyHelper::IsAlive() const {
+  std::lock_guard<priority_recursive_mutex> sync(m_syncMutex);
+  return !m_enabled || m_stopTime > Timer::GetFPGATimestamp();
+}
+
+/**
+ * Check if this motor has exceeded its timeout.
+ *
+ * This method is called periodically to determine if this motor has exceeded
+ * its timeout value. If it has, the stop method is called, and the motor is
+ * shut down until its value is updated again.
+ */
+void MotorSafetyHelper::Check() {
+  DriverStation& ds = DriverStation::GetInstance();
+  if (!m_enabled || ds.IsDisabled() || ds.IsTest()) return;
+
+  std::lock_guard<priority_recursive_mutex> sync(m_syncMutex);
+  if (m_stopTime < Timer::GetFPGATimestamp()) {
+    std::ostringstream desc;
+    m_safeObject->GetDescription(desc);
+    desc << "... Output not updated often enough.";
+    wpi_setWPIErrorWithContext(Timeout, desc.str().c_str());
+    m_safeObject->StopMotor();
+  }
+}
+
+/**
+ * Enable/disable motor safety for this device.
+ *
+ * Turn on and off the motor safety option for this PWM object.
+ *
+ * @param enabled True if motor safety is enforced for this object
+ */
+void MotorSafetyHelper::SetSafetyEnabled(bool enabled) {
+  std::lock_guard<priority_recursive_mutex> sync(m_syncMutex);
+  m_enabled = enabled;
+}
+
+/**
+ * Return the state of the motor safety enabled flag.
+ *
+ * Return if the motor safety is currently enabled for this devicce.
+ *
+ * @return True if motor safety is enforced for this device
+ */
+bool MotorSafetyHelper::IsSafetyEnabled() const {
+  std::lock_guard<priority_recursive_mutex> sync(m_syncMutex);
+  return m_enabled;
+}
+
+/**
+ * Check the motors to see if any have timed out.
+ *
+ * This static method is called periodically to poll all the motors and stop
+ * any that have timed out.
+ */
+void MotorSafetyHelper::CheckMotors() {
+  std::lock_guard<priority_recursive_mutex> sync(m_listMutex);
+  for (auto elem : m_helperList) {
+    elem->Check();
+  }
+}