From ac318b56acfadacd35e68fb6a629829cc576f9e1 Mon Sep 17 00:00:00 2001
From: squidbus <175574877+squidbus@users.noreply.github.com>
Date: Mon, 8 Sep 2025 19:47:12 -0700
Subject: [PATCH] equeue: Few fixes for sceKernelWaitEqueue (#3548)

---
 src/core/libraries/kernel/equeue.cpp | 52 +++++++++++++++-------------
 src/core/libraries/kernel/equeue.h   |  2 +-
 2 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/src/core/libraries/kernel/equeue.cpp b/src/core/libraries/kernel/equeue.cpp
index 06d1b57ac..2190f2533 100644
--- a/src/core/libraries/kernel/equeue.cpp
+++ b/src/core/libraries/kernel/equeue.cpp
@@ -97,7 +97,14 @@ bool EqueueInternal::RemoveEvent(u64 id, s16 filter) {
     return has_found;
 }
 
-int EqueueInternal::WaitForEvents(SceKernelEvent* ev, int num, u32 micros) {
+int EqueueInternal::WaitForEvents(SceKernelEvent* ev, int num, const SceKernelUseconds* timo) {
+    if (timo != nullptr && *timo == 0) {
+        // Effectively acts as a poll; only events that have already
+        // arrived at the time of this function call can be received
+        return GetTriggeredEvents(ev, num);
+    }
+    const auto micros = timo ? *timo : 0u;
+
     if (HasSmallTimer()) {
         // If a small timer is set, just wait for it to expire.
         return WaitForSmallTimer(ev, num, micros);
@@ -111,9 +118,11 @@ int EqueueInternal::WaitForEvents(SceKernelEvent* ev, int num, u32 micros) {
     };
 
     if (micros == 0) {
+        // Wait indefinitely for events
         std::unique_lock lock{m_mutex};
         m_cond.wait(lock, predicate);
     } else {
+        // Wait up until the timeout value
         std::unique_lock lock{m_mutex};
         m_cond.wait_for(lock, std::chrono::microseconds(micros), predicate);
     }
@@ -127,12 +136,6 @@ int EqueueInternal::WaitForEvents(SceKernelEvent* ev, int num, u32 micros) {
         }
     }
 
-    if (ev->flags & SceKernelEvent::Flags::OneShot) {
-        for (auto ev_id = 0u; ev_id < count; ++ev_id) {
-            RemoveEvent(ev->ident, ev->filter);
-        }
-    }
-
     return count;
 }
 
@@ -159,18 +162,27 @@ bool EqueueInternal::TriggerEvent(u64 ident, s16 filter, void* trigger_data) {
 
 int EqueueInternal::GetTriggeredEvents(SceKernelEvent* ev, int num) {
     int count = 0;
-    for (auto& event : m_events) {
-        if (event.IsTriggered()) {
-            // Event should not trigger again
-            event.ResetTriggerState();
+    for (auto it = m_events.begin(); it != m_events.end();) {
+        if (it->IsTriggered()) {
+            ev[count++] = it->event;
 
-            if (event.event.flags & SceKernelEvent::Flags::Clear) {
-                event.Clear();
+            // Event should not trigger again
+            it->ResetTriggerState();
+
+            if (it->event.flags & SceKernelEvent::Flags::Clear) {
+                it->Clear();
             }
-            ev[count++] = event.event;
+            if (it->event.flags & SceKernelEvent::Flags::OneShot) {
+                it = m_events.erase(it);
+            } else {
+                ++it;
+            }
+
             if (count == num) {
                 break;
             }
+        } else {
+            ++it;
         }
     }
 
@@ -277,19 +289,11 @@ int PS4_SYSV_ABI sceKernelWaitEqueue(SceKernelEqueue eq, SceKernelEvent* ev, int
     }
 
     if (num < 1) {
+        *out = 0;
         return ORBIS_KERNEL_ERROR_EINVAL;
     }
 
-    if (timo == nullptr) {
-        // When the timeout is nullptr, we wait indefinitely
-        *out = eq->WaitForEvents(ev, num, 0);
-    } else if (*timo == 0) {
-        // Only events that have already arrived at the time of this function call can be received
-        *out = eq->GetTriggeredEvents(ev, num);
-    } else {
-        // Wait for up to the specified timeout value
-        *out = eq->WaitForEvents(ev, num, *timo);
-    }
+    *out = eq->WaitForEvents(ev, num, timo);
 
     if (*out == 0) {
         return ORBIS_KERNEL_ERROR_ETIMEDOUT;
diff --git a/src/core/libraries/kernel/equeue.h b/src/core/libraries/kernel/equeue.h
index fbc209265..e933f80d1 100644
--- a/src/core/libraries/kernel/equeue.h
+++ b/src/core/libraries/kernel/equeue.h
@@ -153,7 +153,7 @@ public:
     bool ScheduleEvent(u64 id, s16 filter,
                        void (*callback)(SceKernelEqueue, const SceKernelEvent&));
     bool RemoveEvent(u64 id, s16 filter);
-    int WaitForEvents(SceKernelEvent* ev, int num, u32 micros);
+    int WaitForEvents(SceKernelEvent* ev, int num, const SceKernelUseconds* timo);
     bool TriggerEvent(u64 ident, s16 filter, void* trigger_data);
     int GetTriggeredEvents(SceKernelEvent* ev, int num);