[wpiutil] Add mDNS resolver and announcer (#3733)

wpiutil/src/main/native/cpp/MulticastServiceAnnouncer.cpp

@@ -0,0 +1,67 @@
+// 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 "wpi/MulticastServiceAnnouncer.h"
+
+#include <wpi/SmallVector.h>
+
+#include "MulticastHandleManager.h"
+
+extern "C" {
+WPI_MulticastServiceAnnouncerHandle WPI_CreateMulticastServiceAnnouncer(
+    const char* serviceName, const char* serviceType, int32_t port,
+    int32_t txtCount, const char** keys, const char** values)
+
+{
+  auto& manager = wpi::GetMulticastManager();
+  std::scoped_lock lock{manager.mutex};
+
+  wpi::SmallVector<std::pair<std::string_view, std::string_view>, 8> txts;
+
+  for (int32_t i = 0; i < txtCount; i++) {
+    txts.emplace_back(
+        std::pair<std::string_view, std::string_view>{keys[i], values[i]});
+  }
+
+  auto announcer = std::make_unique<wpi::MulticastServiceAnnouncer>(
+      serviceName, serviceType, port, txts);
+
+  size_t index = manager.handleIds.emplace_back(3);
+  manager.announcers[index] = std::move(announcer);
+
+  return index;
+}
+
+void WPI_FreeMulticastServiceAnnouncer(
+    WPI_MulticastServiceAnnouncerHandle handle) {
+  auto& manager = wpi::GetMulticastManager();
+  std::scoped_lock lock{manager.mutex};
+  manager.announcers[handle] = nullptr;
+  manager.handleIds.erase(handle);
+}
+
+void WPI_StartMulticastServiceAnnouncer(
+    WPI_MulticastServiceAnnouncerHandle handle) {
+  auto& manager = wpi::GetMulticastManager();
+  std::scoped_lock lock{manager.mutex};
+  auto& announcer = manager.announcers[handle];
+  announcer->Start();
+}
+
+void WPI_StopMulticastServiceAnnouncer(
+    WPI_MulticastServiceAnnouncerHandle handle) {
+  auto& manager = wpi::GetMulticastManager();
+  std::scoped_lock lock{manager.mutex};
+  auto& announcer = manager.announcers[handle];
+  announcer->Stop();
+}
+
+int32_t WPI_GetMulticastServiceAnnouncerHasImplementation(
+    WPI_MulticastServiceAnnouncerHandle handle) {
+  auto& manager = wpi::GetMulticastManager();
+  std::scoped_lock lock{manager.mutex};
+  auto& announcer = manager.announcers[handle];
+  return announcer->HasImplementation();
+}
+}  // extern "C"