Rate limit outgoing JOIN messages (#3115)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>
Co-authored-by: Tal Neoran <talneoran@gmail.com>

src/util/RatelimitBucket.cpp

@@ -0,0 +1,45 @@
+#include "RatelimitBucket.hpp"
+
+#include <QTimer>
+
+namespace chatterino {
+
+RatelimitBucket::RatelimitBucket(int budget, int cooldown,
+                                 std::function<void(QString)> callback,
+                                 QObject *parent)
+    : QObject(parent)
+    , budget_(budget)
+    , cooldown_(cooldown)
+    , callback_(callback)
+{
+}
+
+void RatelimitBucket::send(QString channel)
+{
+    this->queue_.append(channel);
+
+    if (this->budget_ > 0)
+    {
+        this->handleOne();
+    }
+}
+
+void RatelimitBucket::handleOne()
+{
+    if (queue_.isEmpty())
+    {
+        return;
+    }
+
+    auto item = queue_.takeFirst();
+
+    this->budget_--;
+    callback_(item);
+
+    QTimer::singleShot(cooldown_, this, [this] {
+        this->budget_++;
+        this->handleOne();
+    });
+}
+
+}  // namespace chatterino