[wpinet] Move network portions of wpiutil into new wpinet library (#4077)

wpinet/src/main/native/cpp/uv/Loop.cpp

@@ -0,0 +1,70 @@
+// 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.
+
+#include "wpinet/uv/Loop.h"
+
+using namespace wpi::uv;
+
+Loop::Loop(const private_init&) noexcept {
+#ifndef _WIN32
+  // Ignore SIGPIPE (see https://github.com/joyent/libuv/issues/1254)
+  static bool once = []() {
+    signal(SIGPIPE, SIG_IGN);
+    return true;
+  }();
+  (void)once;
+#endif
+}
+
+Loop::~Loop() noexcept {
+  if (m_loop) {
+    m_loop->data = nullptr;
+    Close();
+  }
+}
+
+std::shared_ptr<Loop> Loop::Create() {
+  auto loop = std::make_shared<Loop>(private_init{});
+  if (uv_loop_init(&loop->m_loopStruct) < 0) {
+    return nullptr;
+  }
+  loop->m_loop = &loop->m_loopStruct;
+  loop->m_loop->data = loop.get();
+  return loop;
+}
+
+std::shared_ptr<Loop> Loop::GetDefault() {
+  static std::shared_ptr<Loop> loop = std::make_shared<Loop>(private_init{});
+  loop->m_loop = uv_default_loop();
+  if (!loop->m_loop) {
+    return nullptr;
+  }
+  loop->m_loop->data = loop.get();
+  return loop;
+}
+
+void Loop::Close() {
+  int err = uv_loop_close(m_loop);
+  if (err < 0) {
+    ReportError(err);
+  }
+}
+
+void Loop::Walk(function_ref<void(Handle&)> callback) {
+  uv_walk(
+      m_loop,
+      [](uv_handle_t* handle, void* func) {
+        auto& h = *static_cast<Handle*>(handle->data);
+        auto& f = *static_cast<function_ref<void(Handle&)>*>(func);
+        f(h);
+      },
+      &callback);
+}
+
+void Loop::Fork() {
+  int err = uv_loop_fork(m_loop);
+  if (err < 0) {
+    ReportError(err);
+  }
+}