Prepare wpiutil for merge into allwpilib.

wpiutil/src/main/native/include/support/Base64.h

@@ -0,0 +1,40 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_BASE64_H_
+#define WPIUTIL_SUPPORT_BASE64_H_
+
+#include <cstddef>
+#include <string>
+
+#include "llvm/StringRef.h"
+
+namespace llvm {
+template <typename T>
+class SmallVectorImpl;
+class raw_ostream;
+}  // namespace llvm
+
+namespace wpi {
+
+size_t Base64Decode(llvm::raw_ostream& os, llvm::StringRef encoded);
+
+size_t Base64Decode(llvm::StringRef encoded, std::string* plain);
+
+llvm::StringRef Base64Decode(llvm::StringRef encoded, size_t* num_read,
+                             llvm::SmallVectorImpl<char>& buf);
+
+void Base64Encode(llvm::raw_ostream& os, llvm::StringRef plain);
+
+void Base64Encode(llvm::StringRef plain, std::string* encoded);
+
+llvm::StringRef Base64Encode(llvm::StringRef plain,
+                             llvm::SmallVectorImpl<char>& buf);
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_BASE64_H_

wpiutil/src/main/native/include/support/ConcurrentQueue.h

@@ -0,0 +1,85 @@
+//
+// Copyright (c) 2013 Juan Palacios juan.palacios.puyana@gmail.com
+// Subject to the BSD 2-Clause License
+// - see < http://opensource.org/licenses/BSD-2-Clause>
+//
+
+#ifndef WPIUTIL_SUPPORT_CONCURRENTQUEUE_H_
+#define WPIUTIL_SUPPORT_CONCURRENTQUEUE_H_
+
+#include <queue>
+#include <thread>
+#include <utility>
+
+#include "support/condition_variable.h"
+#include "support/mutex.h"
+
+namespace wpi {
+
+template <typename T>
+class ConcurrentQueue {
+ public:
+  bool empty() const {
+    std::unique_lock<wpi::mutex> mlock(mutex_);
+    return queue_.empty();
+  }
+
+  typename std::queue<T>::size_type size() const {
+    std::unique_lock<wpi::mutex> mlock(mutex_);
+    return queue_.size();
+  }
+
+  T pop() {
+    std::unique_lock<wpi::mutex> mlock(mutex_);
+    while (queue_.empty()) {
+      cond_.wait(mlock);
+    }
+    auto item = std::move(queue_.front());
+    queue_.pop();
+    return item;
+  }
+
+  void pop(T& item) {
+    std::unique_lock<wpi::mutex> mlock(mutex_);
+    while (queue_.empty()) {
+      cond_.wait(mlock);
+    }
+    item = queue_.front();
+    queue_.pop();
+  }
+
+  void push(const T& item) {
+    std::unique_lock<wpi::mutex> mlock(mutex_);
+    queue_.push(item);
+    mlock.unlock();
+    cond_.notify_one();
+  }
+
+  void push(T&& item) {
+    std::unique_lock<wpi::mutex> mlock(mutex_);
+    queue_.push(std::forward<T>(item));
+    mlock.unlock();
+    cond_.notify_one();
+  }
+
+  template <typename... Args>
+  void emplace(Args&&... args) {
+    std::unique_lock<wpi::mutex> mlock(mutex_);
+    queue_.emplace(std::forward<Args>(args)...);
+    mlock.unlock();
+    cond_.notify_one();
+  }
+
+  ConcurrentQueue() = default;
+  ConcurrentQueue(const ConcurrentQueue&) = delete;
+  ConcurrentQueue& operator=(const ConcurrentQueue&) = delete;
+
+ private:
+  std::queue<T> queue_;
+  mutable wpi::mutex mutex_;
+  wpi::condition_variable cond_;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_CONCURRENTQUEUE_H_

wpiutil/src/main/native/include/support/HttpUtil.h

@@ -0,0 +1,150 @@
+/*----------------------------------------------------------------------------*/
+/* 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_HTTPUTIL_H_
+#define WPIUTIL_SUPPORT_HTTPUTIL_H_
+
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "llvm/ArrayRef.h"
+#include "llvm/SmallString.h"
+#include "llvm/SmallVector.h"
+#include "llvm/StringMap.h"
+#include "llvm/StringRef.h"
+#include "llvm/Twine.h"
+#include "support/raw_istream.h"
+#include "support/raw_socket_istream.h"
+#include "support/raw_socket_ostream.h"
+#include "tcpsockets/NetworkStream.h"
+
+namespace wpi {
+
+// Unescape a %xx-encoded URI.
+// @param buf Buffer for output
+// @param error Set to true if an error occurred
+// @return Escaped string
+llvm::StringRef UnescapeURI(const llvm::Twine& str,
+                            llvm::SmallVectorImpl<char>& buf, bool* error);
+
+// Escape a string with %xx-encoding.
+// @param buf Buffer for output
+// @param spacePlus If true, encodes spaces to '+' rather than "%20"
+// @return Escaped string
+llvm::StringRef EscapeURI(const llvm::Twine& str,
+                          llvm::SmallVectorImpl<char>& buf,
+                          bool spacePlus = true);
+
+// Parse a set of HTTP headers.  Saves just the Content-Type and Content-Length
+// fields.
+// @param is Input stream
+// @param contentType If not null, Content-Type contents are saved here.
+// @param contentLength If not null, Content-Length contents are saved here.
+// @return False if error occurred in input stream
+bool ParseHttpHeaders(wpi::raw_istream& is,
+                      llvm::SmallVectorImpl<char>* contentType,
+                      llvm::SmallVectorImpl<char>* contentLength);
+
+// Look for a MIME multi-part boundary.  On return, the input stream will
+// be located at the character following the boundary (usually "\r\n").
+// @param is Input stream
+// @param boundary Boundary string to scan for (not including "--" prefix)
+// @param saveBuf If not null, all scanned characters up to but not including
+//     the boundary are saved to this string
+// @return False if error occurred on input stream, true if boundary found.
+bool FindMultipartBoundary(wpi::raw_istream& is, llvm::StringRef boundary,
+                           std::string* saveBuf);
+
+class HttpLocation {
+ public:
+  HttpLocation() = default;
+  HttpLocation(const llvm::Twine& url_, bool* error, std::string* errorMsg);
+
+  std::string url;       // retain copy
+  std::string user;      // unescaped
+  std::string password;  // unescaped
+  std::string host;
+  int port;
+  std::string path;  // escaped, not including leading '/'
+  std::vector<std::pair<std::string, std::string>> params;  // unescaped
+  std::string fragment;
+};
+
+class HttpRequest {
+ public:
+  HttpRequest() = default;
+
+  explicit HttpRequest(const HttpLocation& loc)
+      : host{loc.host}, port{loc.port} {
+    SetPath(loc.path, loc.params);
+    SetAuth(loc);
+  }
+
+  template <typename T>
+  HttpRequest(const HttpLocation& loc, const T& extraParams);
+
+  HttpRequest(const HttpLocation& loc, llvm::StringRef path_)
+      : host{loc.host}, port{loc.port}, path{path_} {
+    SetAuth(loc);
+  }
+
+  template <typename T>
+  HttpRequest(const HttpLocation& loc, llvm::StringRef path_, const T& params)
+      : host{loc.host}, port{loc.port} {
+    SetPath(path_, params);
+    SetAuth(loc);
+  }
+
+  llvm::SmallString<128> host;
+  int port;
+  std::string auth;
+  llvm::SmallString<128> path;
+
+ private:
+  void SetAuth(const HttpLocation& loc);
+  template <typename T>
+  void SetPath(llvm::StringRef path_, const T& params);
+
+  template <typename T>
+  static llvm::StringRef GetFirst(const T& elem) {
+    return elem.first;
+  }
+  template <typename T>
+  static llvm::StringRef GetFirst(const llvm::StringMapEntry<T>& elem) {
+    return elem.getKey();
+  }
+  template <typename T>
+  static llvm::StringRef GetSecond(const T& elem) {
+    return elem.second;
+  }
+};
+
+class HttpConnection {
+ public:
+  HttpConnection(std::unique_ptr<wpi::NetworkStream> stream_, int timeout)
+      : stream{std::move(stream_)}, is{*stream, timeout}, os{*stream, true} {}
+
+  bool Handshake(const HttpRequest& request, std::string* warnMsg);
+
+  std::unique_ptr<wpi::NetworkStream> stream;
+  wpi::raw_socket_istream is;
+  wpi::raw_socket_ostream os;
+
+  // Valid after Handshake() is successful
+  llvm::SmallString<64> contentType;
+  llvm::SmallString<64> contentLength;
+
+  explicit operator bool() const { return stream && !is.has_error(); }
+};
+
+}  // namespace wpi
+
+#include "HttpUtil.inl"
+
+#endif  // WPIUTIL_SUPPORT_HTTPUTIL_H_

wpiutil/src/main/native/include/support/HttpUtil.inl

@@ -0,0 +1,48 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2015. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_HTTPUTIL_INL_
+#define WPIUTIL_SUPPORT_HTTPUTIL_INL_
+
+namespace wpi {
+
+template <typename T>
+HttpRequest::HttpRequest(const HttpLocation& loc, const T& extraParams)
+    : host{loc.host}, port{loc.port} {
+  llvm::SmallVector<std::pair<llvm::StringRef, llvm::StringRef>, 8> params;
+  for (const auto& p : loc.params)
+    params.emplace_back(std::make_pair(GetFirst(p), GetSecond(p)));
+  for (const auto& p : extraParams)
+    params.emplace_back(std::make_pair(GetFirst(p), GetSecond(p)));
+  SetPath(loc.path, params);
+  SetAuth(loc);
+}
+
+template <typename T>
+void HttpRequest::SetPath(llvm::StringRef path_, const T& params) {
+  // Build location including query string
+  llvm::raw_svector_ostream pathOs{path};
+  pathOs << path_;
+  bool first = true;
+  for (const auto& param : params) {
+    if (first) {
+      pathOs << '?';
+      first = false;
+    } else {
+      pathOs << '&';
+    }
+    llvm::SmallString<64> escapeBuf;
+    pathOs << EscapeURI(GetFirst(param), escapeBuf);
+    if (!GetSecond(param).empty()) {
+      pathOs << '=' << EscapeURI(GetSecond(param), escapeBuf);
+    }
+  }
+}
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_HTTPUTIL_INL_

wpiutil/src/main/native/include/support/Logger.h

@@ -0,0 +1,100 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_LOGGER_H_
+#define WPIUTIL_SUPPORT_LOGGER_H_
+
+#include <functional>
+
+#include "llvm/SmallString.h"
+#include "llvm/raw_ostream.h"
+
+namespace wpi {
+
+enum LogLevel {
+  WPI_LOG_CRITICAL = 50,
+  WPI_LOG_ERROR = 40,
+  WPI_LOG_WARNING = 30,
+  WPI_LOG_INFO = 20,
+  WPI_LOG_DEBUG = 10,
+  WPI_LOG_DEBUG1 = 9,
+  WPI_LOG_DEBUG2 = 8,
+  WPI_LOG_DEBUG3 = 7,
+  WPI_LOG_DEBUG4 = 6
+};
+
+class Logger {
+ public:
+  typedef std::function<void(unsigned int level, const char* file,
+                             unsigned int line, const char* msg)>
+      LogFunc;
+
+  Logger() = default;
+  explicit Logger(const LogFunc& func) : m_func(func) {}
+  Logger(const LogFunc& func, unsigned int min_level)
+      : m_func(func), m_min_level(min_level) {}
+
+  void SetLogger(LogFunc func) { m_func = func; }
+
+  void set_min_level(unsigned int level) { m_min_level = level; }
+  unsigned int min_level() const { return m_min_level; }
+
+  void Log(unsigned int level, const char* file, unsigned int line,
+           const char* msg) {
+    if (!m_func || level < m_min_level) return;
+    m_func(level, file, line, msg);
+  }
+
+  bool HasLogger() const { return m_func != nullptr; }
+
+ private:
+  LogFunc m_func;
+  unsigned int m_min_level = 20;
+};
+
+#define WPI_LOG(logger_inst, level, x)                                 \
+  do {                                                                 \
+    ::wpi::Logger& WPI_logger_ = logger_inst;                          \
+    if (WPI_logger_.min_level() <= level && WPI_logger_.HasLogger()) { \
+      llvm::SmallString<128> log_buf_;                                 \
+      llvm::raw_svector_ostream log_os_{log_buf_};                     \
+      log_os_ << x;                                                    \
+      WPI_logger_.Log(level, __FILE__, __LINE__, log_buf_.c_str());    \
+    }                                                                  \
+  } while (0)
+
+#define WPI_ERROR(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_ERROR, x)
+#define WPI_WARNING(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_WARNING, x)
+#define WPI_INFO(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_INFO, x)
+
+#ifdef NDEBUG
+#define WPI_DEBUG(inst, x) \
+  do {                     \
+  } while (0)
+#define WPI_DEBUG1(inst, x) \
+  do {                      \
+  } while (0)
+#define WPI_DEBUG2(inst, x) \
+  do {                      \
+  } while (0)
+#define WPI_DEBUG3(inst, x) \
+  do {                      \
+  } while (0)
+#define WPI_DEBUG4(inst, x) \
+  do {                      \
+  } while (0)
+#else
+#define WPI_DEBUG(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_DEBUG, x)
+#define WPI_DEBUG1(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_DEBUG1, x)
+#define WPI_DEBUG2(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_DEBUG2, x)
+#define WPI_DEBUG3(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_DEBUG3, x)
+#define WPI_DEBUG4(inst, x) WPI_LOG(inst, ::wpi::WPI_LOG_DEBUG4, x)
+#endif
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_LOGGER_H_

wpiutil/src/main/native/include/support/SafeThread.h

@@ -0,0 +1,133 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_SAFETHREAD_H_
+#define WPIUTIL_SUPPORT_SAFETHREAD_H_
+
+#include <atomic>
+#include <thread>
+
+#include "support/condition_variable.h"
+#include "support/mutex.h"
+
+namespace wpi {
+
+// Base class for SafeThreadOwner threads.
+class SafeThread {
+ public:
+  SafeThread() { m_active = true; }
+  virtual ~SafeThread() = default;
+  virtual void Main() = 0;
+
+  wpi::mutex m_mutex;
+  std::atomic_bool m_active;
+  wpi::condition_variable m_cond;
+};
+
+namespace detail {
+
+// Non-template proxy base class for common proxy code.
+class SafeThreadProxyBase {
+ public:
+  explicit SafeThreadProxyBase(SafeThread* thr) : m_thread(thr) {
+    if (!m_thread) return;
+    m_lock = std::unique_lock<wpi::mutex>(m_thread->m_mutex);
+    if (!m_thread->m_active) {
+      m_lock.unlock();
+      m_thread = nullptr;
+      return;
+    }
+  }
+  explicit operator bool() const { return m_thread != nullptr; }
+  std::unique_lock<wpi::mutex>& GetLock() { return m_lock; }
+
+ protected:
+  SafeThread* m_thread;
+  std::unique_lock<wpi::mutex> m_lock;
+};
+
+// A proxy for SafeThread.
+// Also serves as a scoped lock on SafeThread::m_mutex.
+template <typename T>
+class SafeThreadProxy : public SafeThreadProxyBase {
+ public:
+  explicit SafeThreadProxy(SafeThread* thr) : SafeThreadProxyBase(thr) {}
+  T& operator*() const { return *static_cast<T*>(m_thread); }
+  T* operator->() const { return static_cast<T*>(m_thread); }
+};
+
+// Non-template owner base class for common owner code.
+class SafeThreadOwnerBase {
+ public:
+  void Stop();
+
+  SafeThreadOwnerBase() { m_thread = nullptr; }
+  SafeThreadOwnerBase(const SafeThreadOwnerBase&) = delete;
+  SafeThreadOwnerBase& operator=(const SafeThreadOwnerBase&) = delete;
+  SafeThreadOwnerBase(SafeThreadOwnerBase&& other)
+      : m_thread(other.m_thread.exchange(nullptr)) {}
+  SafeThreadOwnerBase& operator=(SafeThreadOwnerBase other) {
+    SafeThread* otherthr = other.m_thread.exchange(nullptr);
+    SafeThread* curthr = m_thread.exchange(otherthr);
+    other.m_thread.exchange(curthr);  // other destructor will clean up
+    return *this;
+  }
+  ~SafeThreadOwnerBase() { Stop(); }
+
+  explicit operator bool() const { return m_thread.load(); }
+
+ protected:
+  void Start(SafeThread* thr);
+  SafeThread* GetThread() const { return m_thread.load(); }
+  std::thread::native_handle_type GetNativeThreadHandle() const {
+    return m_nativeHandle;
+  }
+
+ private:
+  std::atomic<SafeThread*> m_thread;
+  std::atomic<std::thread::native_handle_type> m_nativeHandle;
+};
+
+inline void SafeThreadOwnerBase::Start(SafeThread* thr) {
+  SafeThread* curthr = nullptr;
+  SafeThread* newthr = thr;
+  if (!m_thread.compare_exchange_strong(curthr, newthr)) {
+    delete newthr;
+    return;
+  }
+  std::thread stdThread([=]() {
+    newthr->Main();
+    delete newthr;
+  });
+  m_nativeHandle = stdThread.native_handle();
+  stdThread.detach();
+}
+
+inline void SafeThreadOwnerBase::Stop() {
+  SafeThread* thr = m_thread.exchange(nullptr);
+  if (!thr) return;
+  thr->m_active = false;
+  thr->m_cond.notify_one();
+}
+
+}  // namespace detail
+
+template <typename T>
+class SafeThreadOwner : public detail::SafeThreadOwnerBase {
+ public:
+  void Start() { Start(new T); }
+  void Start(T* thr) { detail::SafeThreadOwnerBase::Start(thr); }
+
+  using Proxy = typename detail::SafeThreadProxy<T>;
+  Proxy GetThread() const {
+    return Proxy(detail::SafeThreadOwnerBase::GetThread());
+  }
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_SAFETHREAD_H_

wpiutil/src/main/native/include/support/UidVector.h

@@ -0,0 +1,67 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2017-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_UIDVECTOR_H_
+#define WPIUTIL_SUPPORT_UIDVECTOR_H_
+
+#include <utility>
+#include <vector>
+
+namespace wpi {
+
+// Vector which provides an integrated freelist for removal and reuse of
+// individual elements.
+// @tparam T element type; must be default-constructible and evaluate in
+//           boolean context to false when "empty"
+// @tparam reuse_threshold how many free elements to store up before starting
+//                         to recycle them
+template <typename T, typename std::vector<T>::size_type reuse_threshold>
+class UidVector {
+ public:
+  typedef typename std::vector<T>::size_type size_type;
+
+  bool empty() const { return m_active_count == 0; }
+  size_type size() const { return m_vector.size(); }
+  T& operator[](size_type i) { return m_vector[i]; }
+  const T& operator[](size_type i) const { return m_vector[i]; }
+
+  // Add a new T to the vector.  If there are elements on the freelist,
+  // reuses the last one; otherwise adds to the end of the vector.
+  // Returns the resulting element index.
+  template <class... Args>
+  size_type emplace_back(Args&&... args) {
+    size_type uid;
+    if (m_free.size() < reuse_threshold) {
+      uid = m_vector.size();
+      m_vector.emplace_back(std::forward<Args>(args)...);
+    } else {
+      uid = m_free.front();
+      m_free.erase(m_free.begin());
+      m_vector[uid] = T(std::forward<Args>(args)...);
+    }
+    ++m_active_count;
+    return uid;
+  }
+
+  // Removes the identified element by replacing it with a default-constructed
+  // one.  The element is added to the freelist for later reuse.
+  void erase(size_type uid) {
+    if (uid >= m_vector.size() || !m_vector[uid]) return;
+    m_free.push_back(uid);
+    m_vector[uid] = T();
+    --m_active_count;
+  }
+
+ private:
+  std::vector<T> m_vector;
+  std::vector<size_type> m_free;
+  size_type m_active_count{0};
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_UIDVECTOR_H_

wpiutil/src/main/native/include/support/atomic_static.h

@@ -0,0 +1,49 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_ATOMIC_STATIC_H_
+#define WPIUTIL_SUPPORT_ATOMIC_STATIC_H_
+
+#if !defined(_MSC_VER) || (_MSC_VER >= 1900)
+
+// Just use a local static.  This is thread-safe per
+// http://preshing.com/20130930/double-checked-locking-is-fixed-in-cpp11/
+
+// Per https://msdn.microsoft.com/en-us/library/Hh567368.aspx "Magic Statics"
+// are supported in Visual Studio 2015 but not in earlier versions.
+#define ATOMIC_STATIC(cls, inst) static cls inst
+#define ATOMIC_STATIC_DECL(cls)
+#define ATOMIC_STATIC_INIT(cls)
+
+#else
+// From http://preshing.com/20130930/double-checked-locking-is-fixed-in-cpp11/
+#include <atomic>
+#include <mutex>
+
+#define ATOMIC_STATIC(cls, inst)                               \
+  cls* inst##tmp = m_instance.load(std::memory_order_acquire); \
+  if (inst##tmp == nullptr) {                                  \
+    std::lock_guard<std::mutex> lock(m_instance_mutex);        \
+    inst##tmp = m_instance.load(std::memory_order_relaxed);    \
+    if (inst##tmp == nullptr) {                                \
+      inst##tmp = new cls;                                     \
+      m_instance.store(inst##tmp, std::memory_order_release);  \
+    }                                                          \
+  }                                                            \
+  cls& inst = *inst##tmp
+
+#define ATOMIC_STATIC_DECL(cls)        \
+  static std::atomic<cls*> m_instance; \
+  static std::mutex m_instance_mutex;
+
+#define ATOMIC_STATIC_INIT(cls)      \
+  std::atomic<cls*> cls::m_instance; \
+  std::mutex cls::m_instance_mutex;
+
+#endif
+
+#endif  // WPIUTIL_SUPPORT_ATOMIC_STATIC_H_

wpiutil/src/main/native/include/support/condition_variable.h

@@ -0,0 +1,22 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2017-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <condition_variable>
+
+#include "priority_condition_variable.h"
+
+namespace wpi {
+
+#ifdef WPI_HAVE_PRIORITY_CONDITION_VARIABLE
+using condition_variable = priority_condition_variable;
+#else
+using condition_variable = ::std::condition_variable;
+#endif
+
+}  // namespace wpi

wpiutil/src/main/native/include/support/deprecated.h

@@ -0,0 +1,33 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_DEPRECATED_H_
+#define WPIUTIL_SUPPORT_DEPRECATED_H_
+
+// [[deprecated(msg)]] is a C++14 feature not supported by MSVC or GCC < 4.9.
+// We provide an equivalent warning implementation for those compilers here.
+#ifndef WPI_DEPRECATED
+#if defined(_MSC_VER)
+#define WPI_DEPRECATED(msg) __declspec(deprecated(msg))
+#elif defined(__GNUC__)
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ > 8)
+#if __cplusplus > 201103L
+#define WPI_DEPRECATED(msg) [[deprecated(msg)]]
+#else
+#define WPI_DEPRECATED(msg) [[gnu::deprecated(msg)]]
+#endif
+#else
+#define WPI_DEPRECATED(msg) __attribute__((deprecated(msg)))
+#endif
+#elif __cplusplus > 201103L
+#define WPI_DEPRECATED(msg) [[deprecated(msg)]]
+#else
+#define WPI_DEPRECATED(msg) /*nothing*/
+#endif
+#endif
+
+#endif  // WPIUTIL_SUPPORT_DEPRECATED_H_

wpiutil/src/main/native/include/support/hostname.h

@@ -0,0 +1,25 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2017-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_HOSTNAME_H_
+#define WPIUTIL_SUPPORT_HOSTNAME_H_
+
+#include <string>
+
+#include "llvm/StringRef.h"
+
+namespace llvm {
+template <typename T>
+class SmallVectorImpl;
+}  // namespace llvm
+
+namespace wpi {
+std::string GetHostname();
+llvm::StringRef GetHostname(llvm::SmallVectorImpl<char>& name);
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_HOSTNAME_H_

wpiutil/src/main/native/include/support/jni_util.h

@@ -0,0 +1,615 @@
+/*----------------------------------------------------------------------------*/
+/* 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_JNI_UTIL_H_
+#define WPIUTIL_SUPPORT_JNI_UTIL_H_
+
+#include <jni.h>
+
+#include <queue>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+#include "llvm/ArrayRef.h"
+#include "llvm/ConvertUTF.h"
+#include "llvm/SmallString.h"
+#include "llvm/SmallVector.h"
+#include "llvm/StringRef.h"
+#include "llvm/raw_ostream.h"
+#include "support/SafeThread.h"
+#include "support/atomic_static.h"
+#include "support/deprecated.h"
+#include "support/mutex.h"
+
+namespace wpi {
+namespace java {
+
+// Gets a Java stack trace.  Also provides the last function
+// in the stack trace not starting with excludeFuncPrefix (useful for e.g.
+// finding the first user call to a series of library functions).
+std::string GetJavaStackTrace(
+    JNIEnv* env, std::string* func = nullptr,
+    llvm::StringRef excludeFuncPrefix = llvm::StringRef());
+
+// Shim for backwards compatibility
+template <const char* excludeFuncPrefix>
+WPI_DEPRECATED("use StringRef function instead")
+std::string GetJavaStackTrace(JNIEnv* env, std::string* func) {
+  return GetJavaStackTrace(
+      env, func,
+      excludeFuncPrefix == nullptr ? llvm::StringRef() : excludeFuncPrefix);
+}
+
+// Finds a class and keep it as a global reference.
+// Use with caution, as the destructor does NOT call DeleteGlobalRef due
+// to potential shutdown issues with doing so.
+class JClass {
+ public:
+  JClass() = default;
+
+  JClass(JNIEnv* env, const char* name) {
+    jclass local = env->FindClass(name);
+    if (!local) return;
+    m_cls = static_cast<jclass>(env->NewGlobalRef(local));
+    env->DeleteLocalRef(local);
+  }
+
+  void free(JNIEnv* env) {
+    if (m_cls) env->DeleteGlobalRef(m_cls);
+    m_cls = nullptr;
+  }
+
+  explicit operator bool() const { return m_cls; }
+
+  operator jclass() const { return m_cls; }
+
+ protected:
+  jclass m_cls = nullptr;
+};
+
+// Container class for cleaning up Java local references.
+// The destructor calls DeleteLocalRef.
+template <typename T>
+class JLocal {
+ public:
+  JLocal(JNIEnv* env, T obj) : m_env(env), m_obj(obj) {}
+  JLocal(const JLocal&) = delete;
+  JLocal(JLocal&& oth) : m_env(oth.m_env), m_obj(oth.m_obj) {
+    oth.m_obj = nullptr;
+  }
+  JLocal& operator=(const JLocal&) = delete;
+  JLocal& operator=(JLocal&& oth) {
+    m_env = oth.m_env;
+    m_obj = oth.m_obj;
+    oth.m_obj = nullptr;
+    return *this;
+  }
+  ~JLocal() {
+    if (m_obj) m_env->DeleteLocalRef(m_obj);
+  }
+  operator T() { return m_obj; }
+  T obj() { return m_obj; }
+
+ private:
+  JNIEnv* m_env;
+  T m_obj;
+};
+
+//
+// Conversions from Java objects to C++
+//
+
+// Java string (jstring) reference.  The string is provided as UTF8.
+// This is not actually a reference, as it makes a copy of the string
+// characters, but it's named this way for consistency.
+class JStringRef {
+ public:
+  JStringRef(JNIEnv* env, jstring str) {
+    if (str) {
+      jsize size = env->GetStringLength(str);
+      const jchar* chars = env->GetStringCritical(str, nullptr);
+      if (chars) {
+        llvm::convertUTF16ToUTF8String(llvm::makeArrayRef(chars, size), m_str);
+        env->ReleaseStringCritical(str, chars);
+      }
+    } else {
+      llvm::errs() << "JStringRef was passed a null pointer at \n"
+                   << GetJavaStackTrace(env);
+    }
+    // Ensure str is null-terminated.
+    m_str.push_back('\0');
+    m_str.pop_back();
+  }
+
+  operator llvm::StringRef() const { return m_str; }
+  llvm::StringRef str() const { return m_str; }
+  const char* c_str() const { return m_str.data(); }
+  size_t size() const { return m_str.size(); }
+
+ private:
+  llvm::SmallString<128> m_str;
+};
+
+// Details for J*ArrayRef and CriticalJ*ArrayRef
+namespace detail {
+
+template <typename C, typename T>
+class JArrayRefInner {};
+
+// Specialization of JArrayRefBase to provide StringRef conversion.
+template <typename C>
+class JArrayRefInner<C, jbyte> {
+ public:
+  operator llvm::StringRef() const { return str(); }
+
+  llvm::StringRef str() const {
+    auto arr = static_cast<const C*>(this)->array();
+    if (arr.empty()) return llvm::StringRef{};
+    return llvm::StringRef{reinterpret_cast<const char*>(arr.data()),
+                           arr.size()};
+  }
+};
+
+// Base class for J*ArrayRef and CriticalJ*ArrayRef
+template <typename T>
+class JArrayRefBase : public JArrayRefInner<JArrayRefBase<T>, T> {
+ public:
+  explicit operator bool() const { return this->m_elements != nullptr; }
+
+  operator llvm::ArrayRef<T>() const { return array(); }
+
+  llvm::ArrayRef<T> array() const {
+    if (!this->m_elements) return llvm::ArrayRef<T>{};
+    return llvm::ArrayRef<T>{this->m_elements, this->m_size};
+  }
+
+  JArrayRefBase(const JArrayRefBase&) = delete;
+  JArrayRefBase& operator=(const JArrayRefBase&) = delete;
+
+  JArrayRefBase(JArrayRefBase&& oth)
+      : m_env(oth.m_env),
+        m_jarr(oth.m_jarr),
+        m_size(oth.m_size),
+        m_elements(oth.m_elements) {
+    oth.m_jarr = nullptr;
+    oth.m_elements = nullptr;
+  }
+
+  JArrayRefBase& operator=(JArrayRefBase&& oth) {
+    this->m_env = oth.m_env;
+    this->m_jarr = oth.m_jarr;
+    this->m_size = oth.m_size;
+    this->m_elements = oth.m_elements;
+    oth.m_jarr = nullptr;
+    oth.m_elements = nullptr;
+    return *this;
+  }
+
+ protected:
+  JArrayRefBase(JNIEnv* env, T* elements, size_t size) {
+    this->m_env = env;
+    this->m_jarr = nullptr;
+    this->m_size = size;
+    this->m_elements = elements;
+  }
+
+  JArrayRefBase(JNIEnv* env, jarray jarr) {
+    this->m_env = env;
+    this->m_jarr = jarr;
+    this->m_size = jarr ? env->GetArrayLength(jarr) : 0;
+    this->m_elements = nullptr;
+  }
+
+  JNIEnv* m_env;
+  jarray m_jarr = nullptr;
+  size_t m_size;
+  T* m_elements;
+};
+
+}  // namespace detail
+
+// Java array / DirectBuffer reference.
+
+#define WPI_JNI_JARRAYREF(T, F)                                                \
+  class J##F##ArrayRef : public detail::JArrayRefBase<T> {                     \
+   public:                                                                     \
+    J##F##ArrayRef(JNIEnv* env, jobject bb, int len)                           \
+        : detail::JArrayRefBase<T>(                                            \
+              env,                                                             \
+              static_cast<T*>(bb ? env->GetDirectBufferAddress(bb) : nullptr), \
+              len) {                                                           \
+      if (!bb)                                                                 \
+        llvm::errs() << "JArrayRef was passed a null pointer at \n"            \
+                     << GetJavaStackTrace(env);                                \
+    }                                                                          \
+    J##F##ArrayRef(JNIEnv* env, T##Array jarr)                                 \
+        : detail::JArrayRefBase<T>(env, jarr) {                                \
+      if (jarr)                                                                \
+        m_elements = env->Get##F##ArrayElements(jarr, nullptr);                \
+      else                                                                     \
+        llvm::errs() << "JArrayRef was passed a null pointer at \n"            \
+                     << GetJavaStackTrace(env);                                \
+    }                                                                          \
+    ~J##F##ArrayRef() {                                                        \
+      if (m_jarr && m_elements)                                                \
+        m_env->Release##F##ArrayElements(static_cast<T##Array>(m_jarr),        \
+                                         m_elements, JNI_ABORT);               \
+    }                                                                          \
+  };                                                                           \
+                                                                               \
+  class CriticalJ##F##ArrayRef : public detail::JArrayRefBase<T> {             \
+   public:                                                                     \
+    CriticalJ##F##ArrayRef(JNIEnv* env, T##Array jarr)                         \
+        : detail::JArrayRefBase<T>(env, jarr) {                                \
+      if (jarr)                                                                \
+        m_elements =                                                           \
+            static_cast<T*>(env->GetPrimitiveArrayCritical(jarr, nullptr));    \
+      else                                                                     \
+        llvm::errs() << "JArrayRef was passed a null pointer at \n"            \
+                     << GetJavaStackTrace(env);                                \
+    }                                                                          \
+    ~CriticalJ##F##ArrayRef() {                                                \
+      if (m_jarr && m_elements)                                                \
+        m_env->ReleasePrimitiveArrayCritical(m_jarr, m_elements, JNI_ABORT);   \
+    }                                                                          \
+  };
+
+WPI_JNI_JARRAYREF(jboolean, Boolean)
+WPI_JNI_JARRAYREF(jbyte, Byte)
+WPI_JNI_JARRAYREF(jshort, Short)
+WPI_JNI_JARRAYREF(jint, Int)
+WPI_JNI_JARRAYREF(jlong, Long)
+WPI_JNI_JARRAYREF(jfloat, Float)
+WPI_JNI_JARRAYREF(jdouble, Double)
+
+#undef WPI_JNI_JARRAYREF
+
+//
+// Conversions from C++ to Java objects
+//
+
+// Convert a UTF8 string into a jstring.
+inline jstring MakeJString(JNIEnv* env, llvm::StringRef str) {
+  llvm::SmallVector<UTF16, 128> chars;
+  llvm::convertUTF8ToUTF16String(str, chars);
+  return env->NewString(chars.begin(), chars.size());
+}
+
+// details for MakeJIntArray
+namespace detail {
+
+// Slow path (get primitive array and set individual elements).  This
+// is used if the input type is not an integer of the same size (note
+// signed/unsigned is ignored).
+template <typename T,
+          bool = (std::is_integral<T>::value && sizeof(jint) == sizeof(T))>
+struct ConvertIntArray {
+  static jintArray ToJava(JNIEnv* env, llvm::ArrayRef<T> arr) {
+    jintArray jarr = env->NewIntArray(arr.size());
+    if (!jarr) return nullptr;
+    jint* elements =
+        static_cast<jint*>(env->GetPrimitiveArrayCritical(jarr, nullptr));
+    if (!elements) return nullptr;
+    for (size_t i = 0; i < arr.size(); ++i)
+      elements[i] = static_cast<jint>(arr[i]);
+    env->ReleasePrimitiveArrayCritical(jarr, elements, 0);
+    return jarr;
+  }
+};
+
+// Fast path (use SetIntArrayRegion)
+template <typename T>
+struct ConvertIntArray<T, true> {
+  static jintArray ToJava(JNIEnv* env, llvm::ArrayRef<T> arr) {
+    jintArray jarr = env->NewIntArray(arr.size());
+    if (!jarr) return nullptr;
+    env->SetIntArrayRegion(jarr, 0, arr.size(),
+                           reinterpret_cast<const jint*>(arr.data()));
+    return jarr;
+  }
+};
+
+}  // namespace detail
+
+// Convert an ArrayRef to a jintArray.
+template <typename T>
+inline jintArray MakeJIntArray(JNIEnv* env, llvm::ArrayRef<T> arr) {
+  return detail::ConvertIntArray<T>::ToJava(env, arr);
+}
+
+// Convert a SmallVector to a jintArray.  This is required in addition to
+// ArrayRef because template resolution occurs prior to implicit conversions.
+template <typename T>
+inline jintArray MakeJIntArray(JNIEnv* env,
+                               const llvm::SmallVectorImpl<T>& arr) {
+  return detail::ConvertIntArray<T>::ToJava(env, arr);
+}
+
+// Convert a std::vector to a jintArray.  This is required in addition to
+// ArrayRef because template resolution occurs prior to implicit conversions.
+template <typename T>
+inline jintArray MakeJIntArray(JNIEnv* env, const std::vector<T>& arr) {
+  return detail::ConvertIntArray<T>::ToJava(env, arr);
+}
+
+// Convert a StringRef into a jbyteArray.
+inline jbyteArray MakeJByteArray(JNIEnv* env, llvm::StringRef str) {
+  jbyteArray jarr = env->NewByteArray(str.size());
+  if (!jarr) return nullptr;
+  env->SetByteArrayRegion(jarr, 0, str.size(),
+                          reinterpret_cast<const jbyte*>(str.data()));
+  return jarr;
+}
+
+// Convert an array of integers into a jbooleanArray.
+inline jbooleanArray MakeJBooleanArray(JNIEnv* env, llvm::ArrayRef<int> arr) {
+  jbooleanArray jarr = env->NewBooleanArray(arr.size());
+  if (!jarr) return nullptr;
+  jboolean* elements =
+      static_cast<jboolean*>(env->GetPrimitiveArrayCritical(jarr, nullptr));
+  if (!elements) return nullptr;
+  for (size_t i = 0; i < arr.size(); ++i)
+    elements[i] = arr[i] ? JNI_TRUE : JNI_FALSE;
+  env->ReleasePrimitiveArrayCritical(jarr, elements, 0);
+  return jarr;
+}
+
+// Convert an array of booleans into a jbooleanArray.
+inline jbooleanArray MakeJBooleanArray(JNIEnv* env, llvm::ArrayRef<bool> arr) {
+  jbooleanArray jarr = env->NewBooleanArray(arr.size());
+  if (!jarr) return nullptr;
+  jboolean* elements =
+      static_cast<jboolean*>(env->GetPrimitiveArrayCritical(jarr, nullptr));
+  if (!elements) return nullptr;
+  for (size_t i = 0; i < arr.size(); ++i)
+    elements[i] = arr[i] ? JNI_TRUE : JNI_FALSE;
+  env->ReleasePrimitiveArrayCritical(jarr, elements, 0);
+  return jarr;
+}
+
+  // Other MakeJ*Array conversions.
+
+#define WPI_JNI_MAKEJARRAY(T, F)                                        \
+  inline T##Array MakeJ##F##Array(JNIEnv* env, llvm::ArrayRef<T> arr) { \
+    T##Array jarr = env->New##F##Array(arr.size());                     \
+    if (!jarr) return nullptr;                                          \
+    env->Set##F##ArrayRegion(jarr, 0, arr.size(), arr.data());          \
+    return jarr;                                                        \
+  }
+
+WPI_JNI_MAKEJARRAY(jboolean, Boolean)
+WPI_JNI_MAKEJARRAY(jbyte, Byte)
+WPI_JNI_MAKEJARRAY(jshort, Short)
+WPI_JNI_MAKEJARRAY(jlong, Long)
+WPI_JNI_MAKEJARRAY(jfloat, Float)
+WPI_JNI_MAKEJARRAY(jdouble, Double)
+
+#undef WPI_JNI_MAKEJARRAY
+
+// Convert an array of std::string into a jarray of jstring.
+inline jobjectArray MakeJStringArray(JNIEnv* env,
+                                     llvm::ArrayRef<std::string> arr) {
+  static JClass stringCls{env, "java/lang/String"};
+  if (!stringCls) return nullptr;
+  jobjectArray jarr = env->NewObjectArray(arr.size(), stringCls, nullptr);
+  if (!jarr) return nullptr;
+  for (size_t i = 0; i < arr.size(); ++i) {
+    JLocal<jstring> elem{env, MakeJString(env, arr[i])};
+    env->SetObjectArrayElement(jarr, i, elem.obj());
+  }
+  return jarr;
+}
+
+// Generic callback thread implementation.
+//
+// JNI's AttachCurrentThread() creates a Java Thread object on every
+// invocation, which is both time inefficient and causes issues with Eclipse
+// (which tries to keep a thread list up-to-date and thus gets swamped).
+//
+// Instead, this class attaches just once.  When a hardware notification
+// occurs, a condition variable wakes up this thread and this thread actually
+// makes the call into Java.
+//
+// The template parameter T is the message being passed to the callback, but
+// also needs to provide the following functions:
+//  static JavaVM* GetJVM();
+//  static const char* GetName();
+//  void CallJava(JNIEnv *env, jobject func, jmethodID mid);
+//
+// When creating this, ATOMIC_STATIC_INIT() needs to be performed on the
+// templated class as well.
+template <typename T>
+class JCallbackThread : public SafeThread {
+ public:
+  void Main();
+
+  std::queue<T> m_queue;
+  jobject m_func = nullptr;
+  jmethodID m_mid;
+};
+
+template <typename T>
+class JCallbackManager : public SafeThreadOwner<JCallbackThread<T>> {
+ public:
+  void SetFunc(JNIEnv* env, jobject func, jmethodID mid);
+
+  template <typename... Args>
+  void Send(Args&&... args);
+};
+
+template <typename T>
+void JCallbackManager<T>::SetFunc(JNIEnv* env, jobject func, jmethodID mid) {
+  auto thr = this->GetThread();
+  if (!thr) return;
+  // free global reference
+  if (thr->m_func) env->DeleteGlobalRef(thr->m_func);
+  // create global reference
+  thr->m_func = env->NewGlobalRef(func);
+  thr->m_mid = mid;
+}
+
+template <typename T>
+template <typename... Args>
+void JCallbackManager<T>::Send(Args&&... args) {
+  auto thr = this->GetThread();
+  if (!thr) return;
+  thr->m_queue.emplace(std::forward<Args>(args)...);
+  thr->m_cond.notify_one();
+}
+
+template <typename T>
+void JCallbackThread<T>::Main() {
+  JNIEnv* env;
+  JavaVMAttachArgs args;
+  args.version = JNI_VERSION_1_2;
+  args.name = const_cast<char*>(T::GetName());
+  args.group = nullptr;
+  jint rs = T::GetJVM()->AttachCurrentThreadAsDaemon(
+      reinterpret_cast<void**>(&env), &args);
+  if (rs != JNI_OK) return;
+
+  std::unique_lock<wpi::mutex> lock(m_mutex);
+  while (m_active) {
+    m_cond.wait(lock, [&] { return !(m_active && m_queue.empty()); });
+    if (!m_active) break;
+    while (!m_queue.empty()) {
+      if (!m_active) break;
+      auto item = std::move(m_queue.front());
+      m_queue.pop();
+      auto func = m_func;
+      auto mid = m_mid;
+      lock.unlock();  // don't hold mutex during callback execution
+      item.CallJava(env, func, mid);
+      if (env->ExceptionCheck()) {
+        env->ExceptionDescribe();
+        env->ExceptionClear();
+      }
+      lock.lock();
+    }
+  }
+
+  JavaVM* jvm = T::GetJVM();
+  if (jvm) jvm->DetachCurrentThread();
+}
+
+template <typename T>
+class JSingletonCallbackManager : public JCallbackManager<T> {
+ public:
+  static JSingletonCallbackManager<T>& GetInstance() {
+    ATOMIC_STATIC(JSingletonCallbackManager<T>, instance);
+    return instance;
+  }
+
+ private:
+  ATOMIC_STATIC_DECL(JSingletonCallbackManager<T>)
+};
+
+inline std::string GetJavaStackTrace(JNIEnv* env, std::string* func,
+                                     llvm::StringRef excludeFuncPrefix) {
+  // create a throwable
+  static JClass throwableCls(env, "java/lang/Throwable");
+  if (!throwableCls) return "";
+  static jmethodID constructorId = nullptr;
+  if (!constructorId)
+    constructorId = env->GetMethodID(throwableCls, "<init>", "()V");
+  JLocal<jobject> throwable(env, env->NewObject(throwableCls, constructorId));
+
+  // retrieve information from the exception.
+  // get method id
+  // getStackTrace returns an array of StackTraceElement
+  static jmethodID getStackTraceId = nullptr;
+  if (!getStackTraceId)
+    getStackTraceId = env->GetMethodID(throwableCls, "getStackTrace",
+                                       "()[Ljava/lang/StackTraceElement;");
+
+  // call getStackTrace
+  JLocal<jobjectArray> stackTrace(
+      env, static_cast<jobjectArray>(
+               env->CallObjectMethod(throwable, getStackTraceId)));
+
+  if (!stackTrace) return "";
+
+  // get length of the array
+  jsize stackTraceLength = env->GetArrayLength(stackTrace);
+
+  // get toString methodId of StackTraceElement class
+  static JClass stackTraceElementCls(env, "java/lang/StackTraceElement");
+  if (!stackTraceElementCls) return "";
+  static jmethodID toStringId = nullptr;
+  if (!toStringId)
+    toStringId = env->GetMethodID(stackTraceElementCls, "toString",
+                                  "()Ljava/lang/String;");
+
+  bool haveLoc = false;
+  std::string buf;
+  llvm::raw_string_ostream oss(buf);
+  for (jsize i = 0; i < stackTraceLength; i++) {
+    // add the result of toString method of each element in the result
+    JLocal<jobject> curStackTraceElement(
+        env, env->GetObjectArrayElement(stackTrace, i));
+
+    // call to string on the object
+    JLocal<jstring> stackElementString(
+        env, static_cast<jstring>(
+                 env->CallObjectMethod(curStackTraceElement, toStringId)));
+
+    if (!stackElementString) return "";
+
+    // add a line to res
+    JStringRef elem(env, stackElementString);
+    oss << elem << '\n';
+
+    if (func) {
+      // func is caller of immediate caller (if there was one)
+      // or, if we see it, the first user function
+      if (i == 1) {
+        *func = elem.str();
+      } else if (i > 1 && !haveLoc && !excludeFuncPrefix.empty() &&
+                 !elem.str().startswith(excludeFuncPrefix)) {
+        *func = elem.str();
+        haveLoc = true;
+      }
+    }
+  }
+
+  return oss.str();
+}
+
+// Finds an exception class and keep it as a global reference.
+// Similar to JClass, but provides Throw methods.
+// Use with caution, as the destructor does NOT call DeleteGlobalRef due
+// to potential shutdown issues with doing so.
+class JException : public JClass {
+ public:
+  JException() = default;
+  JException(JNIEnv* env, const char* name) : JClass(env, name) {
+    if (m_cls)
+      m_constructor =
+          env->GetMethodID(m_cls, "<init>", "(Ljava/lang/String;)V");
+  }
+
+  void Throw(JNIEnv* env, jstring msg) {
+    jobject exception = env->NewObject(m_cls, m_constructor, msg);
+    env->Throw(static_cast<jthrowable>(exception));
+  }
+
+  void Throw(JNIEnv* env, llvm::StringRef msg) {
+    Throw(env, MakeJString(env, msg));
+  }
+
+  explicit operator bool() const { return m_constructor; }
+
+ private:
+  jmethodID m_constructor = nullptr;
+};
+
+}  // namespace java
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_JNI_UTIL_H_

wpiutil/src/main/native/include/support/leb128.h

@@ -0,0 +1,26 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_LEB128_H_
+#define WPIUTIL_SUPPORT_LEB128_H_
+
+#include <cstddef>
+
+#include "llvm/SmallVector.h"
+
+namespace wpi {
+
+class raw_istream;
+
+uint64_t SizeUleb128(uint64_t val);
+uint64_t WriteUleb128(llvm::SmallVectorImpl<char>& dest, uint64_t val);
+uint64_t ReadUleb128(const char* addr, uint64_t* ret);
+bool ReadUleb128(raw_istream& is, uint64_t* ret);
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_LEB128_H_

wpiutil/src/main/native/include/support/mutex.h

@@ -0,0 +1,24 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2017-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <mutex>
+
+#include "priority_mutex.h"
+
+namespace wpi {
+
+#ifdef WPI_HAVE_PRIORITY_MUTEX
+using mutex = priority_mutex;
+using recursive_mutex = priority_recursive_mutex;
+#else
+using mutex = ::std::mutex;
+using recursive_mutex = ::std::recursive_mutex;
+#endif
+
+}  // namespace wpi

wpiutil/src/main/native/include/support/priority_condition_variable.h

@@ -0,0 +1,122 @@
+/*----------------------------------------------------------------------------*/
+/* 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#ifdef __linux__
+#include <pthread.h>
+#endif
+
+#include <condition_variable>
+#include <memory>
+#include <utility>
+
+#include "priority_mutex.h"
+
+namespace wpi {
+
+#if defined(__linux__) && defined(WPI_HAVE_PRIORITY_MUTEX)
+
+#define WPI_HAVE_PRIORITY_CONDITION_VARIABLE 1
+
+class priority_condition_variable {
+  typedef std::chrono::system_clock clock;
+
+ public:
+  typedef pthread_cond_t* native_handle_type;
+
+  priority_condition_variable() noexcept = default;
+  ~priority_condition_variable() noexcept { pthread_cond_destroy(&m_cond); }
+
+  priority_condition_variable(const priority_condition_variable&) = delete;
+  priority_condition_variable& operator=(const priority_condition_variable&) =
+      delete;
+
+  void notify_one() noexcept { pthread_cond_signal(&m_cond); }
+
+  void notify_all() noexcept { pthread_cond_broadcast(&m_cond); }
+
+  void wait(std::unique_lock<priority_mutex>& lock) noexcept {
+    int e = pthread_cond_wait(&m_cond, lock.mutex()->native_handle());
+    if (e) std::terminate();
+  }
+
+  template <typename Predicate>
+  void wait(std::unique_lock<priority_mutex>& lock, Predicate p) {
+    while (!p()) {
+      wait(lock);
+    }
+  }
+
+  template <typename Duration>
+  std::cv_status wait_until(
+      std::unique_lock<priority_mutex>& lock,
+      const std::chrono::time_point<clock, Duration>& atime) {
+    return wait_until_impl(lock, atime);
+  }
+
+  template <typename Clock, typename Duration>
+  std::cv_status wait_until(
+      std::unique_lock<priority_mutex>& lock,
+      const std::chrono::time_point<Clock, Duration>& atime) {
+    const typename Clock::time_point c_entry = Clock::now();
+    const clock::time_point s_entry = clock::now();
+    const auto delta = atime - c_entry;
+    const auto s_atime = s_entry + delta;
+
+    return wait_until_impl(lock, s_atime);
+  }
+
+  template <typename Clock, typename Duration, typename Predicate>
+  bool wait_until(std::unique_lock<priority_mutex>& lock,
+                  const std::chrono::time_point<Clock, Duration>& atime,
+                  Predicate p) {
+    while (!p()) {
+      if (wait_until(lock, atime) == std::cv_status::timeout) {
+        return p();
+      }
+    }
+    return true;
+  }
+
+  template <typename Rep, typename Period>
+  std::cv_status wait_for(std::unique_lock<priority_mutex>& lock,
+                          const std::chrono::duration<Rep, Period>& rtime) {
+    return wait_until(lock, clock::now() + rtime);
+  }
+
+  template <typename Rep, typename Period, typename Predicate>
+  bool wait_for(std::unique_lock<priority_mutex>& lock,
+                const std::chrono::duration<Rep, Period>& rtime, Predicate p) {
+    return wait_until(lock, clock::now() + rtime, std::move(p));
+  }
+
+  native_handle_type native_handle() { return &m_cond; }
+
+ private:
+  pthread_cond_t m_cond = PTHREAD_COND_INITIALIZER;
+
+  template <typename Dur>
+  std::cv_status wait_until_impl(
+      std::unique_lock<priority_mutex>& lock,
+      const std::chrono::time_point<clock, Dur>& atime) {
+    auto s = std::chrono::time_point_cast<std::chrono::seconds>(atime);
+    auto ns = std::chrono::duration_cast<std::chrono::nanoseconds>(atime - s);
+
+    struct timespec ts = {
+        static_cast<std::time_t>(s.time_since_epoch().count()),
+        static_cast<long>(ns.count())};  // NOLINT(runtime/int)
+
+    pthread_cond_timedwait(&m_cond, lock.mutex()->native_handle(), &ts);
+
+    return (clock::now() < atime ? std::cv_status::no_timeout
+                                 : std::cv_status::timeout);
+  }
+};
+#endif
+
+}  // namespace wpi

wpiutil/src/main/native/include/support/priority_mutex.h

@@ -0,0 +1,84 @@
+/*----------------------------------------------------------------------------*/
+/* 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+// Allows usage with std::lock_guard without including <mutex> separately
+#ifdef __linux__
+#include <pthread.h>
+#endif
+
+#include <mutex>
+
+namespace wpi {
+
+#ifdef __linux__
+
+#define WPI_HAVE_PRIORITY_MUTEX 1
+
+class priority_recursive_mutex {
+ public:
+  typedef pthread_mutex_t* native_handle_type;
+
+  constexpr priority_recursive_mutex() noexcept = default;
+  priority_recursive_mutex(const priority_recursive_mutex&) = delete;
+  priority_recursive_mutex& operator=(const priority_recursive_mutex&) = delete;
+
+  // Lock the mutex, blocking until it's available.
+  void lock() { pthread_mutex_lock(&m_mutex); }
+
+  // Unlock the mutex.
+  void unlock() { pthread_mutex_unlock(&m_mutex); }
+
+  // Tries to lock the mutex.
+  bool try_lock() noexcept { return !pthread_mutex_trylock(&m_mutex); }
+
+  pthread_mutex_t* native_handle() { return &m_mutex; }
+
+ private:
+// Do the equivalent of setting PTHREAD_PRIO_INHERIT and
+// PTHREAD_MUTEX_RECURSIVE_NP.
+#ifdef __PTHREAD_MUTEX_HAVE_PREV
+  pthread_mutex_t m_mutex = {
+      {0, 0, 0, 0, 0x20 | PTHREAD_MUTEX_RECURSIVE_NP, __PTHREAD_SPINS, {0, 0}}};
+#else
+  pthread_mutex_t m_mutex = {
+      {0, 0, 0, 0x20 | PTHREAD_MUTEX_RECURSIVE_NP, 0, {__PTHREAD_SPINS}}};
+#endif
+};
+
+class priority_mutex {
+ public:
+  typedef pthread_mutex_t* native_handle_type;
+
+  constexpr priority_mutex() noexcept = default;
+  priority_mutex(const priority_mutex&) = delete;
+  priority_mutex& operator=(const priority_mutex&) = delete;
+
+  // Lock the mutex, blocking until it's available.
+  void lock() { pthread_mutex_lock(&m_mutex); }
+
+  // Unlock the mutex.
+  void unlock() { pthread_mutex_unlock(&m_mutex); }
+
+  // Tries to lock the mutex.
+  bool try_lock() noexcept { return !pthread_mutex_trylock(&m_mutex); }
+
+  pthread_mutex_t* native_handle() { return &m_mutex; }
+
+ private:
+// Do the equivalent of setting PTHREAD_PRIO_INHERIT.
+#ifdef __PTHREAD_MUTEX_HAVE_PREV
+  pthread_mutex_t m_mutex = {{0, 0, 0, 0, 0x20, __PTHREAD_SPINS, {0, 0}}};
+#else
+  pthread_mutex_t m_mutex = {{0, 0, 0, 0x20, 0, {__PTHREAD_SPINS}}};
+#endif
+};
+
+#endif  // __linux__
+
+}  // namespace wpi

wpiutil/src/main/native/include/support/raw_istream.h

@@ -0,0 +1,115 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_RAW_ISTREAM_H_
+#define WPIUTIL_SUPPORT_RAW_ISTREAM_H_
+
+#include <algorithm>
+#include <cstddef>
+#include <system_error>
+
+#include "llvm/SmallVector.h"
+#include "llvm/StringRef.h"
+#include "llvm/Twine.h"
+
+namespace wpi {
+
+class raw_istream {
+ public:
+  raw_istream() = default;
+  virtual ~raw_istream() = default;
+
+  raw_istream& read(char& c) {
+    read_impl(&c, 1);
+    return *this;
+  }
+
+  raw_istream& read(unsigned char& c) {
+    read_impl(&c, 1);
+    return *this;
+  }
+
+  raw_istream& read(signed char& c) {
+    read_impl(&c, 1);
+    return *this;
+  }
+
+  raw_istream& read(void* data, size_t len) {
+    read_impl(data, len);
+    return *this;
+  }
+
+  size_t readsome(void* data, size_t len) {
+    size_t readlen = std::min(in_avail(), len);
+    if (readlen == 0) return 0;
+    read_impl(data, readlen);
+    return readlen;
+  }
+
+  // Read a line from an input stream (up to a maximum length).
+  // The returned buffer will contain the trailing \n (unless the maximum length
+  // was reached).  \r's are stripped from the buffer.
+  // @param buf Buffer for output
+  // @param maxLen Maximum length
+  // @return Line
+  llvm::StringRef getline(llvm::SmallVectorImpl<char>& buf, int maxLen);
+
+  virtual void close() = 0;
+  virtual size_t in_avail() const = 0;
+
+  bool has_error() const { return m_error; }
+  void clear_error() { m_error = false; }
+
+  raw_istream(const raw_istream&) = delete;
+  raw_istream& operator=(const raw_istream&) = delete;
+
+ protected:
+  void error_detected() { m_error = true; }
+
+ private:
+  virtual void read_impl(void* data, size_t len) = 0;
+
+  bool m_error = false;
+};
+
+class raw_mem_istream : public raw_istream {
+ public:
+  explicit raw_mem_istream(llvm::StringRef mem);
+  raw_mem_istream(const char* mem, size_t len) : m_cur(mem), m_left(len) {}
+  void close() override;
+  size_t in_avail() const override;
+
+ private:
+  void read_impl(void* data, size_t len) override;
+
+  const char* m_cur;
+  size_t m_left;
+};
+
+class raw_fd_istream : public raw_istream {
+ public:
+  raw_fd_istream(const llvm::Twine& filename, std::error_code& ec,
+                 size_t bufSize = 4096);
+  raw_fd_istream(int fd, bool shouldClose, size_t bufSize = 4096);
+  ~raw_fd_istream() override;
+  void close() override;
+  size_t in_avail() const override;
+
+ private:
+  void read_impl(void* data, size_t len) override;
+
+  char* m_buf;
+  char* m_cur;
+  char* m_end;
+  size_t m_bufSize;
+  int m_fd;
+  bool m_shouldClose;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_RAW_ISTREAM_H_

wpiutil/src/main/native/include/support/raw_socket_istream.h

@@ -0,0 +1,34 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_RAW_SOCKET_ISTREAM_H_
+#define WPIUTIL_SUPPORT_RAW_SOCKET_ISTREAM_H_
+
+#include "support/raw_istream.h"
+
+namespace wpi {
+
+class NetworkStream;
+
+class raw_socket_istream : public raw_istream {
+ public:
+  explicit raw_socket_istream(NetworkStream& stream, int timeout = 0)
+      : m_stream(stream), m_timeout(timeout) {}
+
+  void close() override;
+  size_t in_avail() const override;
+
+ private:
+  void read_impl(void* data, size_t len) override;
+
+  NetworkStream& m_stream;
+  int m_timeout;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_RAW_SOCKET_ISTREAM_H_

wpiutil/src/main/native/include/support/raw_socket_ostream.h

@@ -0,0 +1,42 @@
+/*----------------------------------------------------------------------------*/
+/* 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_RAW_SOCKET_OSTREAM_H_
+#define WPIUTIL_SUPPORT_RAW_SOCKET_OSTREAM_H_
+
+#include "llvm/raw_ostream.h"
+
+namespace wpi {
+
+class NetworkStream;
+
+class raw_socket_ostream : public llvm::raw_ostream {
+ public:
+  raw_socket_ostream(NetworkStream& stream, bool shouldClose)
+      : m_stream(stream), m_shouldClose(shouldClose) {}
+  ~raw_socket_ostream();
+
+  void close();
+
+  bool has_error() const { return m_error; }
+  void clear_error() { m_error = false; }
+
+ protected:
+  void error_detected() { m_error = true; }
+
+ private:
+  void write_impl(const char* data, size_t len) override;
+  uint64_t current_pos() const override;
+
+  NetworkStream& m_stream;
+  bool m_error = false;
+  bool m_shouldClose;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_RAW_SOCKET_OSTREAM_H_

wpiutil/src/main/native/include/support/sha1.h

@@ -0,0 +1,56 @@
+/*
+    sha1.hpp - header of
+
+    ============
+    SHA-1 in C++
+    ============
+
+    100% Public Domain.
+
+    Original C Code
+        -- Steve Reid <steve@edmweb.com>
+    Small changes to fit into bglibs
+        -- Bruce Guenter <bruce@untroubled.org>
+    Translation to simpler C++ Code
+        -- Volker Grabsch <vog@notjusthosting.com>
+    Safety fixes
+        -- Eugene Hopkinson <slowriot at voxelstorm dot com>
+*/
+
+#ifndef WPIUTIL_SUPPORT_SHA1_H_
+#define WPIUTIL_SUPPORT_SHA1_H_
+
+#include <stdint.h>
+
+#include <string>
+
+#include "llvm/StringRef.h"
+
+namespace llvm {
+template <typename T>
+class SmallVectorImpl;
+}  // namespace llvm
+
+namespace wpi {
+
+class raw_istream;
+
+class SHA1 {
+ public:
+  SHA1();
+  void Update(llvm::StringRef s);
+  void Update(raw_istream& is);
+  std::string Final();
+  llvm::StringRef Final(llvm::SmallVectorImpl<char>& buf);
+  static std::string FromFile(llvm::StringRef filename);
+
+ private:
+  uint32_t digest[5];
+  unsigned char buffer[64];
+  size_t buf_size;
+  uint64_t transforms;
+};
+
+}  // namespace wpi
+
+#endif  // WPIUTIL_SUPPORT_SHA1_H_

wpiutil/src/main/native/include/support/timestamp.h

@@ -0,0 +1,71 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2015-2018 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#ifndef WPIUTIL_SUPPORT_TIMESTAMP_H_
+#define WPIUTIL_SUPPORT_TIMESTAMP_H_
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * The default implementation used for Now().
+ * In general this is the time returned by the operating system.
+ * @return Time in microseconds.
+ */
+uint64_t WPI_NowDefault(void);
+
+/**
+ * Set the implementation used by WPI_Now().
+ * The implementation must return monotonic time in microseconds to maintain
+ * the contract of WPI_Now().
+ * @param func Function called by WPI_Now() to return the time.
+ */
+void WPI_SetNowImpl(uint64_t (*func)(void));
+
+/**
+ * Return a value representing the current time in microseconds.
+ * The epoch is not defined.
+ * @return Time in microseconds.
+ */
+uint64_t WPI_Now(void);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#ifdef __cplusplus
+namespace wpi {
+
+/**
+ * The default implementation used for Now().
+ * In general this is the time returned by the operating system.
+ * @return Time in microseconds.
+ */
+uint64_t NowDefault(void);
+
+/**
+ * Set the implementation used by Now().
+ * The implementation must return monotonic time in microseconds to maintain
+ * the contract of Now().
+ * @param func Function called by Now() to return the time.
+ */
+void SetNowImpl(uint64_t (*func)());
+
+/**
+ * Return a value representing the current time in microseconds.
+ * This is a monotonic clock with an undefined epoch.
+ * @return Time in microseconds.
+ */
+uint64_t Now(void);
+
+}  // namespace wpi
+#endif
+
+#endif  // WPIUTIL_SUPPORT_TIMESTAMP_H_