From c17ea5437146075ccfdd1368e14cceb97d02a6f6 Mon Sep 17 00:00:00 2001
From: outfoxxed <outfoxxed@outfoxxed.me>
Date: Fri, 20 Jun 2025 16:37:22 -0700
Subject: [PATCH] wayland/lock: check for protocol availability before use

Fixes #66
---
 src/wayland/session_lock.cpp              | 7 +++++++
 src/wayland/session_lock/session_lock.cpp | 2 ++
 src/wayland/session_lock/session_lock.hpp | 2 ++
 3 files changed, 11 insertions(+)

diff --git a/src/wayland/session_lock.cpp b/src/wayland/session_lock.cpp
index ccba9bc..0ecf9ec 100644
--- a/src/wayland/session_lock.cpp
+++ b/src/wayland/session_lock.cpp
@@ -109,6 +109,13 @@ void WlSessionLock::updateSurfaces(bool show, WlSessionLock* old) {
 
 void WlSessionLock::realizeLockTarget(WlSessionLock* old) {
 	if (this->lockTarget) {
+		if (!SessionLockManager::lockAvailable()) {
+			qCritical() << "Cannot start session lock: The current compositor does not support the "
+			               "ext-session-lock-v1 protocol.";
+			this->unlock();
+			return;
+		}
+
 		if (this->mSurfaceComponent == nullptr) {
 			qWarning() << "WlSessionLock.surface is null. Aborting lock.";
 			this->unlock();
diff --git a/src/wayland/session_lock/session_lock.cpp b/src/wayland/session_lock/session_lock.cpp
index 50e8818..c32dd90 100644
--- a/src/wayland/session_lock/session_lock.cpp
+++ b/src/wayland/session_lock/session_lock.cpp
@@ -22,6 +22,8 @@ QSWaylandSessionLockManager* manager() {
 }
 } // namespace
 
+bool SessionLockManager::lockAvailable() { return manager()->isActive(); }
+
 bool SessionLockManager::lock() {
 	if (this->isLocked() || SessionLockManager::sessionLocked()) return false;
 	this->mLock = manager()->acquireLock();
diff --git a/src/wayland/session_lock/session_lock.hpp b/src/wayland/session_lock/session_lock.hpp
index 1ad6ae9..5a55896 100644
--- a/src/wayland/session_lock/session_lock.hpp
+++ b/src/wayland/session_lock/session_lock.hpp
@@ -15,6 +15,8 @@ class SessionLockManager: public QObject {
 public:
 	explicit SessionLockManager(QObject* parent = nullptr): QObject(parent) {}
 
+	[[nodiscard]] static bool lockAvailable();
+
 	// Returns true if a lock was acquired.
 	// If true is returned the caller must watch the global screen list and create/destroy
 	// windows with an attached LockWindowExtension to match it.