feat: gracefully shut down on SIGINT/SIGTERM on Linux/mac (#6053)

src/util/UnixSignalHandler.cpp

@@ -0,0 +1,83 @@
+#include <QtGlobal>
+
+#if defined(Q_OS_UNIX)
+
+#    include "common/QLogging.hpp"
+#    include "util/UnixSignalHandler.hpp"
+
+#    include <QPointer>
+#    include <sys/socket.h>
+#    include <unistd.h>
+
+#    include <csignal>
+#    include <unordered_map>
+
+namespace {
+
+using namespace chatterino;
+
+std::unordered_map<int, QPointer<UnixSignalHandler>> HANDLERS{};
+
+}  // namespace
+
+namespace chatterino {
+
+UnixSignalHandler::UnixSignalHandler(int signal)
+{
+    if (::socketpair(AF_UNIX, SOCK_STREAM, 0, this->fd.data()) != 0)
+    {
+        qCWarning(chatterinoApp)
+            << "Failed to create UnixSignalHandler for" << signal;
+        return;
+    }
+
+    this->socketNotifier =
+        new QSocketNotifier(this->fd[1], QSocketNotifier::Read, this);
+
+    QObject::connect(this->socketNotifier, &QSocketNotifier::activated, this,
+                     &UnixSignalHandler::handleSignal);
+
+    struct sigaction action;
+    action.sa_handler = UnixSignalHandler::fired;
+    sigemptyset(&action.sa_mask);
+    action.sa_flags = 0;
+    action.sa_flags |= SA_RESTART;
+
+    if (sigaction(signal, &action, nullptr) != 0)
+    {
+        qCWarning(chatterinoApp) << "Failed to listen to signal for" << signal;
+        return;
+    }
+
+    HANDLERS[signal] = QPointer(this);
+}
+
+void UnixSignalHandler::fired(int signal)
+{
+    const auto &cls = HANDLERS[signal];
+    assert(!cls.isNull());
+    if (cls.isNull())
+    {
+        qCWarning(chatterinoApp)
+            << "unix signal fired without a registered handler";
+        return;
+    }
+
+    char a = 1;
+    ::write(cls->fd[0], &a, sizeof(a));
+}
+
+void UnixSignalHandler::handleSignal()
+{
+    this->socketNotifier->setEnabled(false);
+
+    char tmp{};
+    ::read(this->fd[1], &tmp, sizeof(tmp));
+
+    this->socketNotifier->setEnabled(true);
+
+    this->signalFired();
+}
+
+}  // namespace chatterino
+#endif