init

cmake/external/glib/cppgir/examples/gio.cpp

@@ -0,0 +1,98 @@
+#define GI_INLINE 1
+#include <gio/gio.hpp>
+
+#include <iostream>
+
+namespace GLib = gi::repository::GLib;
+namespace Gio = gi::repository::Gio;
+
+const std::string localhost("127.0.0.1");
+static GLib::MainLoop loop;
+
+// many calls here support GError
+// so typically will throw here instead
+// (unless GError output is explicitly requested in call signature)
+
+// NOTE abundancy of gi::expect not generally needed;
+// only needed when using --dl and --expected
+
+static bool
+receive(Gio::Socket s, GLib::IOCondition /*cond*/)
+{
+  guint8 buffer[1024] = {
+      0,
+  };
+  Gio::SocketAddress a;
+  int count = gi::expect(s.receive_from(&a, buffer, sizeof(buffer)));
+  if (count > 0) {
+    // let's see where it came from
+    std::string origin("someone");
+    auto ia = gi::object_cast<Gio::InetSocketAddress>(a);
+    if (ia) {
+      origin = gi::expect(gi::expect(ia.get_address()).to_string());
+      origin += ":";
+      origin += std::to_string(gi::expect(ia.get_port()));
+    }
+    std::cout << origin << " said " << (char *)buffer << std::endl;
+    // quit when idle
+    GLib::idle_add([]() {
+      loop.quit();
+      return GLib::SOURCE_REMOVE_;
+    });
+  }
+  return true;
+}
+
+Gio::Socket
+open(bool listen)
+{
+  auto socket = gi::expect(Gio::Socket::new_(Gio::SocketFamily::IPV4_,
+      Gio::SocketType::DATAGRAM_, Gio::SocketProtocol::DEFAULT_));
+
+  auto address =
+      gi::expect(Gio::InetSocketAddress::new_from_string(localhost, 0));
+  socket.bind(address, false);
+  socket.set_blocking(false);
+
+  if (listen) {
+    // runtime introspection has a hard time here,
+    // but with a bit of extra information, we can keep going
+#if defined(GI_CALL_ARGS) && CALL_ARGS <= 1
+    // so we should have this signature for a function with 1 non-required
+    GLib::Source source =
+        gi::expect(socket.create_source({.condition = GLib::IOCondition::IN_}));
+#else
+    GLib::Source source =
+        gi::expect(socket.create_source(GLib::IOCondition::IN_, nullptr));
+#endif
+    source.set_callback<Gio::SocketSourceFunc>(receive);
+    source.attach();
+  }
+
+  return socket;
+}
+
+static void
+die(const std::string &why)
+{
+  std::cerr << why << std::endl;
+  exit(2);
+}
+
+int
+main(int argc, char **argv)
+{
+  if (argc < 2)
+    die("missing argument");
+
+  std::string msg = argv[1];
+  std::cout << "will send message " << msg << std::endl;
+
+  auto recv = open(true);
+  auto local = gi::expect(recv.get_local_address());
+  auto send = open(false);
+  send.send_to(local, (guint8 *)msg.data(), msg.size(), nullptr);
+
+  loop = gi::expect(GLib::MainLoop::new_());
+  loop.run();
+}