1 files changed, 114 insertions, 0 deletions
diff --git a/src/bun.js/bindings/webcore/EventSender.h b/src/bun.js/bindings/webcore/EventSender.h
new file mode 100644
index 000000000..d69a6e5e9
--- /dev/null
+++ b/src/bun.js/bindings/webcore/EventSender.h
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2012 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "Timer.h"
+#include <wtf/Vector.h>
+#include <wtf/WeakPtr.h>
+
+namespace WebCore {
+
+class Page;
+
+template<typename T> class EventSender {
+    WTF_MAKE_NONCOPYABLE(EventSender); WTF_MAKE_FAST_ALLOCATED;
+public:
+    explicit EventSender(const AtomString& eventType);
+
+    const AtomString& eventType() const { return m_eventType; }
+    void dispatchEventSoon(T&);
+    void cancelEvent(T&);
+    void dispatchPendingEvents(Page*);
+
+#if ASSERT_ENABLED
+    bool hasPendingEvents(T& sender) const
+    {
+        return m_dispatchSoonList.find(&sender) != notFound || m_dispatchingList.find(&sender) != notFound;
+    }
+#endif
+
+private:
+    void timerFired() { dispatchPendingEvents(nullptr); }
+
+    AtomString m_eventType;
+    Timer m_timer;
+    Vector<WeakPtr<T>> m_dispatchSoonList;
+    Vector<WeakPtr<T>> m_dispatchingList;
+};
+
+template<typename T> EventSender<T>::EventSender(const AtomString& eventType)
+    : m_eventType(eventType)
+    , m_timer(*this, &EventSender::timerFired)
+{
+}
+
+template<typename T> void EventSender<T>::dispatchEventSoon(T& sender)
+{
+    m_dispatchSoonList.append(sender);
+    if (!m_timer.isActive())
+        m_timer.startOneShot(0_s);
+}
+
+template<typename T> void EventSender<T>::cancelEvent(T& sender)
+{
+    // Remove instances of this sender from both lists.
+    // Use loops because we allow multiple instances to get into the lists.
+    for (auto& event : m_dispatchSoonList) {
+        if (event == &sender)
+            event = nullptr;
+    }
+    for (auto& event : m_dispatchingList) {
+        if (event == &sender)
+            event = nullptr;
+    }
+}
+
+template<typename T> void EventSender<T>::dispatchPendingEvents(Page* page)
+{
+    // Need to avoid re-entering this function; if new dispatches are
+    // scheduled before the parent finishes processing the list, they
+    // will set a timer and eventually be processed.
+    if (!m_dispatchingList.isEmpty())
+        return;
+
+    m_timer.stop();
+
+    m_dispatchSoonList.checkConsistency();
+
+    m_dispatchingList = std::exchange(m_dispatchSoonList, { });
+    for (auto& event : m_dispatchingList) {
+        if (auto sender = event.get()) {
+            event = nullptr;
+            if (!page || sender->document().page() == page)
+                sender->dispatchPendingEvent(this);
+            else
+                dispatchEventSoon(*sender);
+        }
+    }
+    m_dispatchingList.clear();
+}
+
+} // namespace WebCore