launch: replace hard-link WebEngine with QLibrary dynamic loading

CMakeLists.txt

@@ -81,14 +81,6 @@ boption(SERVICE_UPOWER "UPower" ON)
 boption(SERVICE_NOTIFICATIONS "Notifications" ON)
 boption(BLUETOOTH "Bluetooth" ON)
 boption(NETWORK "Network" ON)
-boption(WEBENGINE "WebEngine" ON)
-
-if (WEBENGINE_effective AND USE_JEMALLOC_effective)
-	message(FATAL_ERROR "WEBENGINE and USE_JEMALLOC are incompatible. "
-		"Chromium's PartitionAlloc conflicts with jemalloc. "
-		"Set -DUSE_JEMALLOC=OFF to use WebEngine.")
-endif()
-
 include(cmake/install-qml-module.cmake)
 include(cmake/util.cmake)
 
@@ -144,10 +136,6 @@ if (DBUS)
 	list(APPEND QT_FPDEPS DBus)
 endif()
 
-if (WEBENGINE_effective)
-	list(APPEND QT_FPDEPS WebEngineQuick)
-endif()
-
 find_package(Qt6 REQUIRED COMPONENTS ${QT_FPDEPS})
 
 # In Qt 6.10, private dependencies are required to be explicit,

src/CMakeLists.txt

@@ -10,6 +10,7 @@ add_subdirectory(ipc)
 add_subdirectory(window)
 add_subdirectory(io)
 add_subdirectory(widgets)
+add_subdirectory(webengine)
 add_subdirectory(ui)
 
 if (CRASH_HANDLER)

src/build/CMakeLists.txt

@@ -15,12 +15,6 @@ else()
 	set(CRASH_HANDLER_DEF 0)
 endif()
 
-if (WEBENGINE)
-	set(WEBENGINE_DEF 1)
-else()
-	set(WEBENGINE_DEF 0)
-endif()
-
 configure_file(build.hpp.in build.hpp @ONLY ESCAPE_QUOTES)
 
 target_include_directories(quickshell-build INTERFACE ${CMAKE_CURRENT_BINARY_DIR})

src/build/build.hpp.in

@@ -9,7 +9,6 @@
 #define GIT_REVISION "@GIT_REVISION@"
 #define DISTRIBUTOR "@DISTRIBUTOR@"
 #define CRASH_HANDLER @CRASH_HANDLER_DEF@
-#define WEBENGINE @WEBENGINE_DEF@
 #define BUILD_TYPE "@CMAKE_BUILD_TYPE@"
 #define COMPILER "@CMAKE_CXX_COMPILER_ID@ (@CMAKE_CXX_COMPILER_VERSION@)"
 #define COMPILE_FLAGS "@CMAKE_CXX_FLAGS@"

src/launch/CMakeLists.txt

@@ -20,8 +20,4 @@ qs_add_pchset(launch
 
 qs_pch(quickshell-launch SET launch)
 
-if (WEBENGINE)
-	target_link_libraries(quickshell-launch PRIVATE Qt::WebEngineQuick)
-endif()
-
 target_link_libraries(quickshell PRIVATE quickshell-launch)

src/launch/launch.cpp

@@ -31,9 +31,7 @@
 #include "../crash/handler.hpp"
 #endif
 
-#if WEBENGINE
-#include <qtwebenginequickglobal.h>
-#endif
+#include "../webengine/webengine.hpp"
 
 namespace qs::launch {
 
@@ -96,6 +94,7 @@ int launch(const LaunchArgs& args, char** argv, QCoreApplication* coreApplicatio
 			else if (pragma == "NativeTextRendering") pragmas.nativeTextRendering = true;
 			else if (pragma == "IgnoreSystemSettings") pragmas.desktopSettingsAware = false;
 			else if (pragma == "RespectSystemStyle") pragmas.useSystemStyle = true;
+			else if (pragma == "UseWebEngine") pragmas.useWebEngine = true;
 			else if (pragma.startsWith("IconTheme ")) pragmas.iconTheme = pragma.sliced(10);
 			else if (pragma.startsWith("Env ")) {
 				auto envPragma = pragma.sliced(4);
@@ -117,8 +116,7 @@ int launch(const LaunchArgs& args, char** argv, QCoreApplication* coreApplicatio
 				pragmas.stateDir = pragma.sliced(9).trimmed();
 			} else if (pragma.startsWith("CacheDir ")) {
 				pragmas.cacheDir = pragma.sliced(9).trimmed();
-			} else if (pragma == "UseWebEngine") pragmas.useWebEngine = true;
-			else {
+			} else {
 				qCritical() << "Unrecognized pragma" << pragma;
 				return -1;
 			}
@@ -231,11 +229,9 @@ int launch(const LaunchArgs& args, char** argv, QCoreApplication* coreApplicatio
 	QGuiApplication* app = nullptr;
 	auto qArgC = 1; // argv[0] must be valid; Chromium requires it, Qt won't consume it
 
-#if WEBENGINE
 	if (pragmas.useWebEngine) {
-		QtWebEngineQuick::initialize();
+		qs::web_engine::init();
 	}
-#endif
 
 	if (pragmas.useQApplication) {
 		app = new QApplication(qArgC, argv);

src/webengine/CMakeLists.txt

@@ -0,0 +1,3 @@
+if (BUILD_TESTING)
+	add_subdirectory(test)
+endif()

src/webengine/test/CMakeLists.txt

@@ -0,0 +1,3 @@
+add_executable(webengine webengine.cpp)
+target_link_libraries(webengine PRIVATE Qt::Core Qt::Test)
+add_test(NAME webengine WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}" COMMAND $<TARGET_FILE:webengine>)

src/webengine/test/manual/webengine.qml

@@ -0,0 +1,14 @@
+//@ pragma UseWebEngine
+
+import Quickshell
+import QtWebEngine
+
+FloatingWindow {
+	width: 800
+	height: 600
+
+	WebEngineView {
+		anchors.fill: parent
+		url: "data:text/html,<h1>WebEngine works</h1><p>If you see this, QtWebEngineQuick initialized correctly.</p>"
+	}
+}

src/webengine/test/webengine.cpp

@@ -0,0 +1,10 @@
+#include "webengine.hpp"
+
+#include <qtest.h>
+#include <qtestcase.h>
+
+#include "../webengine.hpp"
+
+void WebEngineInitTest::init() { QVERIFY(qs::web_engine::init()); }
+
+QTEST_MAIN(WebEngineInitTest)

src/webengine/test/webengine.hpp

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <qobject.h>
+#include <qtmetamacros.h>
+
+class WebEngineInitTest: public QObject {
+	Q_OBJECT;
+
+private slots:
+	static void init();
+};

src/webengine/webengine.hpp

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <qdebug.h>
+#include <qlibrary.h>
+#include <qlogging.h>
+
+namespace qs::web_engine {
+
+inline bool init() {
+	using InitializeFunc = void (*)();
+
+	QLibrary lib("Qt6WebEngineQuick");
+	if (!lib.load()) {
+		qWarning() << "Failed to load library:" << lib.errorString();
+		qWarning() << "You might need to install the necessary package for Qt6WebEngineQuick.";
+		qWarning() << "QtWebEngineQuick is not loaded. Using the qml type WebEngineView from"
+		              " QtWebEngine might lead to undefined behaviour!";
+		return false;
+	}
+
+	qDebug() << "Loaded library Qt6WebEngineQuick";
+
+	auto initialize =
+	    reinterpret_cast<InitializeFunc>(lib.resolve("_ZN16QtWebEngineQuick10initializeEv")); // NOLINT
+	if (!initialize) {
+		qWarning() << "Failed to resolve symbol 'void QtWebEngineQuick::initialize()' in lib"
+		              " Qt6WebEngineQuick. This should not happen.";
+		qWarning() << "QtWebEngineQuick is not loaded. Using the qml type WebEngineView from"
+		              " QtWebEngine might lead to undefined behaviour!";
+		return false;
+	}
+
+	qDebug() << "Found symbol QtWebEngineQuick::initialize(). Initializing WebEngine...";
+
+	initialize();
+
+	qWarning() << "WebEngine initialized. Note: WebEngine is incompatible with jemalloc."
+	              " If quickshell crashes immediately, rebuild with -DUSE_JEMALLOC=OFF.";
+
+	qDebug() << "Successfully initialized QtWebEngineQuick";
+	return true;
+}
+
+} // namespace qs::web_engine