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

CHANGELOG.md

@@ -44,6 +44,7 @@
 - Dev: Subscriptions to PubSub channel points redemption topics now use no auth token, making it continue to work during PubSub shutdown. (#5947)
 - Dev: Add initial experimental EventSub support. (#5837, #5895, #5897, #5904, #5910, #5903, #5915, #5916, #5930, #5935, #5932, #5943, #5952, #5953, #5968, #5973, #5974, #5980, #5981, #5985, #5990, #5992, #5993, #5996, #5995, #6000, #6001, #6002, #6003, #6005, #6007, #6010, #6008, #6012, #6013, #6015, #6017, #6027, #6028, #6035, #6036, #6040, #6041, #6048)
 - Dev: Remove unneeded platform specifier for toasts. (#5914)
+- Dev: Cleanly shutdown on `SIGINT`/`SIGTERM` on Linux & macOS. (#6053)
 - Dev: Highlight checks now use non-capturing groups for the boundaries. (#5784)
 - Dev: Removed unused PubSub whisper code. (#5898)
 - Dev: Updated Conan dependencies. (#5776)

src/CMakeLists.txt

@@ -547,6 +547,8 @@ set(SOURCE_FILES
         util/Twitch.cpp
         util/Twitch.hpp
         util/TypeName.hpp
+        util/UnixSignalHandler.cpp
+        util/UnixSignalHandler.hpp
         util/Variant.hpp
         util/VectorMessageSink.cpp
         util/VectorMessageSink.hpp

src/RunGui.cpp

@@ -11,6 +11,7 @@
 #include "singletons/Settings.hpp"
 #include "singletons/Updates.hpp"
 #include "util/CombinePath.hpp"
+#include "util/UnixSignalHandler.hpp"
 #include "widgets/dialogs/LastRunCrashDialog.hpp"
 
 #include <QApplication>
@@ -172,6 +173,21 @@ namespace {
 
         signal(SIGSEGV, handleSignal);
 #endif
+
+#if defined(Q_OS_UNIX)
+        auto *sigintHandler = new UnixSignalHandler(SIGINT);
+        QObject::connect(sigintHandler, &UnixSignalHandler::signalFired, [] {
+            qCInfo(chatterinoApp)
+                << "Received SIGINT, request application quit";
+            QApplication::quit();
+        });
+        auto *sigtermHandler = new UnixSignalHandler(SIGTERM);
+        QObject::connect(sigtermHandler, &UnixSignalHandler::signalFired, [] {
+            qCInfo(chatterinoApp)
+                << "Received SIGTERM, request application quit";
+            QApplication::quit();
+        });
+#endif
     }
 
     // We delete cache files that haven't been modified in 14 days. This strategy may be

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

src/util/UnixSignalHandler.hpp

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <QtGlobal>
+
+#if defined(Q_OS_UNIX)
+#    include <QObject>
+#    include <QSocketNotifier>
+
+#    include <array>
+
+namespace chatterino {
+
+class UnixSignalHandler : public QObject
+{
+    Q_OBJECT
+
+public:
+    UnixSignalHandler(int signal);
+
+    static void fired(int signal);
+
+Q_SIGNALS:
+    void signalFired();
+
+private:
+    void handleSignal();
+
+    std::array<int, 2> fd{};
+    QSocketNotifier *socketNotifier;
+};
+
+}  // namespace chatterino
+
+#endif