1 files changed, 162 insertions, 0 deletions
diff --git a/src/core/hle/service/am/event_observer.cpp b/src/core/hle/service/am/event_observer.cpp
new file mode 100644
index 000000000..5d1d303ed
--- /dev/null
+++ b/src/core/hle/service/am/event_observer.cpp
@@ -0,0 +1,162 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/core.h"
+#include "core/hle/kernel/k_event.h"
+#include "core/hle/service/am/applet.h"
+#include "core/hle/service/am/event_observer.h"
+#include "core/hle/service/am/window_system.h"
+
+namespace Service::AM {
+
+enum class UserDataTag : u32 {
+    WakeupEvent,
+    AppletProcess,
+};
+
+EventObserver::EventObserver(Core::System& system, WindowSystem& window_system)
+    : m_system(system), m_context(system, "am:EventObserver"), m_window_system(window_system),
+      m_wakeup_event(m_context), m_wakeup_holder(m_wakeup_event.GetHandle()) {
+    m_window_system.SetEventObserver(this);
+    m_wakeup_holder.SetUserData(static_cast<uintptr_t>(UserDataTag::WakeupEvent));
+    m_wakeup_holder.LinkToMultiWait(std::addressof(m_multi_wait));
+    m_thread = std::thread([&] { this->ThreadFunc(); });
+}
+
+EventObserver::~EventObserver() {
+    // Signal thread and wait for processing to finish.
+    m_stop_source.request_stop();
+    m_wakeup_event.Signal();
+    m_thread.join();
+
+    // Free remaining owned sessions.
+    auto it = m_process_holder_list.begin();
+    while (it != m_process_holder_list.end()) {
+        // Get the holder.
+        auto* const holder = std::addressof(*it);
+
+        // Remove from the list.
+        it = m_process_holder_list.erase(it);
+
+        // Free the holder.
+        delete holder;
+    }
+}
+
+void EventObserver::TrackAppletProcess(Applet& applet) {
+    // Don't observe dummy processes.
+    if (!applet.process->IsInitialized()) {
+        return;
+    }
+
+    // Allocate new holder.
+    auto* holder = new ProcessHolder(applet, *applet.process);
+    holder->SetUserData(static_cast<uintptr_t>(UserDataTag::AppletProcess));
+
+    // Insert into list.
+    {
+        std::scoped_lock lk{m_lock};
+        m_process_holder_list.push_back(*holder);
+        holder->LinkToMultiWait(std::addressof(m_deferred_wait_list));
+    }
+
+    // Signal wakeup.
+    m_wakeup_event.Signal();
+}
+
+void EventObserver::RequestUpdate() {
+    m_wakeup_event.Signal();
+}
+
+void EventObserver::LinkDeferred() {
+    std::scoped_lock lk{m_lock};
+    m_multi_wait.MoveAll(std::addressof(m_deferred_wait_list));
+}
+
+MultiWaitHolder* EventObserver::WaitSignaled() {
+    while (true) {
+        this->LinkDeferred();
+
+        // If we're done, return before we start waiting.
+        if (m_stop_source.stop_requested()) {
+            return nullptr;
+        }
+
+        auto* selected = m_multi_wait.WaitAny(m_system.Kernel());
+        if (selected != std::addressof(m_wakeup_holder)) {
+            // Unlink the process.
+            selected->UnlinkFromMultiWait();
+        }
+
+        return selected;
+    }
+}
+
+void EventObserver::Process(MultiWaitHolder* holder) {
+    switch (static_cast<UserDataTag>(holder->GetUserData())) {
+    case UserDataTag::WakeupEvent:
+        this->OnWakeupEvent(holder);
+        break;
+    case UserDataTag::AppletProcess:
+        this->OnProcessEvent(static_cast<ProcessHolder*>(holder));
+        break;
+    default:
+        UNREACHABLE();
+    }
+}
+
+void EventObserver::OnWakeupEvent(MultiWaitHolder* holder) {
+    m_wakeup_event.Clear();
+
+    // Perform recalculation.
+    m_window_system.Update();
+}
+
+void EventObserver::OnProcessEvent(ProcessHolder* holder) {
+    // Check process state.
+    auto& applet = holder->GetApplet();
+    auto& process = holder->GetProcess();
+
+    {
+        std::scoped_lock lk{m_lock, applet.lock};
+        if (process.IsTerminated()) {
+            // Destroy the holder.
+            this->DestroyAppletProcessHolderLocked(holder);
+        } else {
+            // Reset signaled state.
+            process.ResetSignal();
+
+            // Relink wakeup event.
+            holder->LinkToMultiWait(std::addressof(m_deferred_wait_list));
+        }
+
+        // Set running.
+        applet.is_process_running = process.IsRunning();
+    }
+
+    // Perform recalculation.
+    m_window_system.Update();
+}
+
+void EventObserver::DestroyAppletProcessHolderLocked(ProcessHolder* holder) {
+    // Remove from owned list.
+    m_process_holder_list.erase(m_process_holder_list.iterator_to(*holder));
+
+    // Destroy and free.
+    delete holder;
+}
+
+void EventObserver::ThreadFunc() {
+    Common::SetCurrentThreadName("am:EventObserver");
+
+    while (true) {
+        auto* signaled_holder = this->WaitSignaled();
+        if (!signaled_holder) {
+            break;
+        }
+
+        this->Process(signaled_holder);
+    }
+}
+
+} // namespace Service::AM