Squashed 'third_party/allwpilib_2019/' content from commit bd05dfa1c

Change-Id: I2b1c2250cdb9b055133780c33593292098c375b7
git-subtree-dir: third_party/allwpilib_2019
git-subtree-split: bd05dfa1c7cca74c4fac451e7b9d6a37e7b53447
diff --git a/hal/src/main/native/sim/Notifier.cpp b/hal/src/main/native/sim/Notifier.cpp
new file mode 100644
index 0000000..9f549d5
--- /dev/null
+++ b/hal/src/main/native/sim/Notifier.cpp
@@ -0,0 +1,159 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2016-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "hal/Notifier.h"
+
+#include <chrono>
+
+#include <wpi/condition_variable.h>
+#include <wpi/mutex.h>
+#include <wpi/timestamp.h>
+
+#include "HALInitializer.h"
+#include "hal/HAL.h"
+#include "hal/cpp/fpga_clock.h"
+#include "hal/handles/UnlimitedHandleResource.h"
+
+namespace {
+struct Notifier {
+  uint64_t waitTime;
+  bool updatedAlarm = false;
+  bool active = true;
+  bool running = false;
+  wpi::mutex mutex;
+  wpi::condition_variable cond;
+};
+}  // namespace
+
+using namespace hal;
+
+class NotifierHandleContainer
+    : public UnlimitedHandleResource<HAL_NotifierHandle, Notifier,
+                                     HAL_HandleEnum::Notifier> {
+ public:
+  ~NotifierHandleContainer() {
+    ForEach([](HAL_NotifierHandle handle, Notifier* notifier) {
+      {
+        std::lock_guard<wpi::mutex> lock(notifier->mutex);
+        notifier->active = false;
+        notifier->running = false;
+      }
+      notifier->cond.notify_all();  // wake up any waiting threads
+    });
+  }
+};
+
+static NotifierHandleContainer* notifierHandles;
+
+namespace hal {
+namespace init {
+void InitializeNotifier() {
+  static NotifierHandleContainer nH;
+  notifierHandles = &nH;
+}
+}  // namespace init
+}  // namespace hal
+
+extern "C" {
+
+HAL_NotifierHandle HAL_InitializeNotifier(int32_t* status) {
+  hal::init::CheckInit();
+  std::shared_ptr<Notifier> notifier = std::make_shared<Notifier>();
+  HAL_NotifierHandle handle = notifierHandles->Allocate(notifier);
+  if (handle == HAL_kInvalidHandle) {
+    *status = HAL_HANDLE_ERROR;
+    return HAL_kInvalidHandle;
+  }
+  return handle;
+}
+
+void HAL_StopNotifier(HAL_NotifierHandle notifierHandle, int32_t* status) {
+  auto notifier = notifierHandles->Get(notifierHandle);
+  if (!notifier) return;
+
+  {
+    std::lock_guard<wpi::mutex> lock(notifier->mutex);
+    notifier->active = false;
+    notifier->running = false;
+  }
+  notifier->cond.notify_all();
+}
+
+void HAL_CleanNotifier(HAL_NotifierHandle notifierHandle, int32_t* status) {
+  auto notifier = notifierHandles->Free(notifierHandle);
+  if (!notifier) return;
+
+  // Just in case HAL_StopNotifier() wasn't called...
+  {
+    std::lock_guard<wpi::mutex> lock(notifier->mutex);
+    notifier->active = false;
+    notifier->running = false;
+  }
+  notifier->cond.notify_all();
+}
+
+void HAL_UpdateNotifierAlarm(HAL_NotifierHandle notifierHandle,
+                             uint64_t triggerTime, int32_t* status) {
+  auto notifier = notifierHandles->Get(notifierHandle);
+  if (!notifier) return;
+
+  {
+    std::lock_guard<wpi::mutex> lock(notifier->mutex);
+    notifier->waitTime = triggerTime;
+    notifier->running = true;
+    notifier->updatedAlarm = true;
+  }
+
+  // We wake up any waiters to change how long they're sleeping for
+  notifier->cond.notify_all();
+}
+
+void HAL_CancelNotifierAlarm(HAL_NotifierHandle notifierHandle,
+                             int32_t* status) {
+  auto notifier = notifierHandles->Get(notifierHandle);
+  if (!notifier) return;
+
+  {
+    std::lock_guard<wpi::mutex> lock(notifier->mutex);
+    notifier->running = false;
+  }
+}
+
+uint64_t HAL_WaitForNotifierAlarm(HAL_NotifierHandle notifierHandle,
+                                  int32_t* status) {
+  auto notifier = notifierHandles->Get(notifierHandle);
+  if (!notifier) return 0;
+
+  std::unique_lock<wpi::mutex> lock(notifier->mutex);
+  while (notifier->active) {
+    double waitTime;
+    if (!notifier->running) {
+      waitTime = (HAL_GetFPGATime(status) * 1e-6) + 1000.0;
+      // If not running, wait 1000 seconds
+    } else {
+      waitTime = notifier->waitTime * 1e-6;
+    }
+
+    // Don't wait twice
+    notifier->updatedAlarm = false;
+
+    auto timeoutTime =
+        hal::fpga_clock::epoch() + std::chrono::duration<double>(waitTime);
+    notifier->cond.wait_until(lock, timeoutTime);
+    if (notifier->updatedAlarm) {
+      notifier->updatedAlarm = false;
+      continue;
+    }
+    if (!notifier->running) continue;
+    if (!notifier->active) break;
+    notifier->running = false;
+    return HAL_GetFPGATime(status);
+  }
+  return 0;
+}
+
+}  // extern "C"