From 6f030e60bf0ab210c0a92eb04afcbe7ef2ca7792 Mon Sep 17 00:00:00 2001
From: Maroun Deeb <maround95@gmail.com>
Date: Tue, 7 Jan 2025 18:37:04 +0200
Subject: [PATCH] GPU hotplug support

---
 src/managers/eventLoop/EventLoopManager.cpp | 30 ++++++++++++++++-----
 src/managers/eventLoop/EventLoopManager.hpp | 22 +++++++++++----
 2 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/src/managers/eventLoop/EventLoopManager.cpp b/src/managers/eventLoop/EventLoopManager.cpp
index db8b49b6ebd..aaa6c107b0f 100644
--- a/src/managers/eventLoop/EventLoopManager.cpp
+++ b/src/managers/eventLoop/EventLoopManager.cpp
@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <limits>
 
+#include <map>
 #include <sys/timerfd.h>
 #include <ctime>
 
@@ -16,11 +17,12 @@ CEventLoopManager::CEventLoopManager(wl_display* display, wl_event_loop* wlEvent
     m_sTimers.timerfd  = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
     m_sWayland.loop    = wlEventLoop;
     m_sWayland.display = display;
+    aqEventSources     = std::map<int, SEventSourceData>{};
 }
 
 CEventLoopManager::~CEventLoopManager() {
-    for (auto const& eventSource : m_sWayland.aqEventSources) {
-        wl_event_source_remove(eventSource);
+    for (auto const& [_, eventSourceData] : aqEventSources) {
+        wl_event_source_remove(eventSourceData.eventSource);
     }
 
     if (m_sWayland.eventSource)
@@ -45,10 +47,8 @@ static int aquamarineFDWrite(int fd, uint32_t mask, void* data) {
 void CEventLoopManager::enterLoop() {
     m_sWayland.eventSource = wl_event_loop_add_fd(m_sWayland.loop, m_sTimers.timerfd, WL_EVENT_READABLE, timerWrite, nullptr);
 
-    aqPollFDs = g_pCompositor->m_pAqBackend->getPollFDs();
-    for (auto const& fd : aqPollFDs) {
-        m_sWayland.aqEventSources.emplace_back(wl_event_loop_add_fd(m_sWayland.loop, fd->fd, WL_EVENT_READABLE, aquamarineFDWrite, fd.get()));
-    }
+    syncPollFDs();
+    m_sListeners.pollFDsChanged = g_pCompositor->m_pAqBackend->events.pollFDsChanged.registerListener([this](std::any d) { syncPollFDs(); });
 
     // if we have a session, dispatch it to get the pending input devices
     if (g_pCompositor->m_pAqBackend->hasSession())
@@ -133,3 +133,21 @@ void CEventLoopManager::doLater(const std::function<void()>& fn) {
         },
         &m_sIdle);
 }
+
+void CEventLoopManager::syncPollFDs() {
+    auto aqPollFDs = g_pCompositor->m_pAqBackend->getPollFDs();
+
+    for (auto it = aqEventSources.begin(); it != aqEventSources.end();) {
+        if (std::ranges::all_of(aqPollFDs, [&](SP<Aquamarine::SPollFD> fd) { return fd->fd != it->first; })) {
+            wl_event_source_remove(it->second.eventSource);
+            it = aqEventSources.erase(it);
+        } else {
+            ++it;
+        }
+    }
+
+    for (auto& fd : aqPollFDs | std::views::filter([&](SP<Aquamarine::SPollFD> fd) { return !aqEventSources.contains(fd->fd); })) {
+        auto eventSource       = wl_event_loop_add_fd(m_sWayland.loop, fd->fd, WL_EVENT_READABLE, aquamarineFDWrite, fd.get());
+        aqEventSources[fd->fd] = {.pollFD = fd, .eventSource = eventSource};
+    }
+}
diff --git a/src/managers/eventLoop/EventLoopManager.hpp b/src/managers/eventLoop/EventLoopManager.hpp
index 39d8bbebafa..96a984a2fe2 100644
--- a/src/managers/eventLoop/EventLoopManager.hpp
+++ b/src/managers/eventLoop/EventLoopManager.hpp
@@ -4,6 +4,7 @@
 #include <mutex>
 #include <thread>
 #include <wayland-server.h>
+#include "helpers/signal/Signal.hpp"
 
 #include "EventLoopTimer.hpp"
 
@@ -36,11 +37,18 @@ class CEventLoopManager {
     };
 
   private:
+    // Manages the event sources after AQ pollFDs change.
+    void syncPollFDs();
+
+    struct SEventSourceData {
+        SP<Aquamarine::SPollFD> pollFD;
+        wl_event_source*        eventSource = nullptr;
+    };
+
     struct {
-        wl_event_loop*                loop        = nullptr;
-        wl_display*                   display     = nullptr;
-        wl_event_source*              eventSource = nullptr;
-        std::vector<wl_event_source*> aqEventSources;
+        wl_event_loop*   loop        = nullptr;
+        wl_display*      display     = nullptr;
+        wl_event_source* eventSource = nullptr;
     } m_sWayland;
 
     struct {
@@ -49,7 +57,11 @@ class CEventLoopManager {
     } m_sTimers;
 
     SIdleData                            m_sIdle;
-    std::vector<SP<Aquamarine::SPollFD>> aqPollFDs;
+    std::map<int, SEventSourceData>      aqEventSources;
+
+    struct {
+        CHyprSignalListener pollFDsChanged;
+    } m_sListeners;
 
     friend class CSyncTimeline;
 };