core/log: capture early logs in fs logger

src/core/CMakeLists.txt

@@ -39,7 +39,6 @@ qt_add_library(quickshell-core STATIC
 	clock.cpp
 	logging.cpp
 	paths.cpp
-	filelogger.cpp
 )
 
 set_source_files_properties(main.cpp PROPERTIES COMPILE_DEFINITIONS GIT_REVISION="${GIT_REVISION}")

src/core/filelogger.cpp

@@ -1,60 +0,0 @@
-#include "filelogger.hpp"
-
-#include <qlogging.h>
-#include <qloggingcategory.h>
-#include <qnamespace.h>
-#include <qobject.h>
-#include <qobjectdefs.h>
-#include <qtextstream.h>
-
-#include "filelogger_p.hpp"
-#include "logging.hpp"
-#include "paths.hpp"
-
-Q_LOGGING_CATEGORY(logLogger, "quickshell.logger", QtWarningMsg);
-
-void FileLoggerThread::init() {
-	auto* thread = new FileLoggerThread();
-	auto* logger = new FileLogger();
-	logger->moveToThread(thread);
-	thread->start();
-	QMetaObject::invokeMethod(logger, "init", Qt::BlockingQueuedConnection);
-}
-
-void FileLogger::init() {
-	qCDebug(logLogger) << "Initializing filesystem logger...";
-	auto* runDir = QsPaths::instance()->instanceRunDir();
-
-	if (!runDir) {
-		qCCritical(logLogger
-		) << "Could not start filesystem logger as the runtime directory could not be created.";
-		return;
-	}
-
-	auto path = runDir->filePath("log.log");
-	auto* file = new QFile(path);
-
-	if (!file->open(QFile::WriteOnly | QFile::Truncate)) {
-		qCCritical(logLogger
-		) << "Could not start filesystem logger as the log file could not be created:"
-		  << path;
-		return;
-	}
-
-	this->fileStream.setDevice(file);
-
-	QObject::connect(
-	    LogManager::instance(),
-	    &LogManager::logMessage,
-	    this,
-	    &FileLogger::onMessage,
-	    Qt::QueuedConnection
-	);
-
-	qDebug(logLogger) << "Initialized filesystem logger";
-}
-
-void FileLogger::onMessage(const LogMessage& msg) {
-	LogManager::formatMessage(this->fileStream, msg, false, true);
-	this->fileStream << Qt::endl;
-}

src/core/filelogger.hpp

@@ -1,13 +0,0 @@
-#pragma once
-
-#include <qthread.h>
-#include <qtmetamacros.h>
-class FileLoggerThread: public QThread {
-	Q_OBJECT;
-
-public:
-	static void init();
-
-private:
-	explicit FileLoggerThread() = default;
-};

src/core/filelogger_p.hpp

@@ -1,24 +0,0 @@
-#pragma once
-
-#include <qfile.h>
-#include <qobject.h>
-#include <qtextstream.h>
-#include <qtmetamacros.h>
-
-#include "logging.hpp"
-
-class FileLogger: public QObject {
-	Q_OBJECT;
-
-public:
-	explicit FileLogger() = default;
-
-public slots:
-	void init();
-
-private slots:
-	void onMessage(const LogMessage& msg);
-
-private:
-	QTextStream fileStream;
-};

src/core/logging.cpp

@@ -3,14 +3,25 @@
 #include <cstring>
 
 #include <qlogging.h>
+#include <qloggingcategory.h>
+#include <qnamespace.h>
+#include <qobject.h>
+#include <qobjectdefs.h>
 #include <qstring.h>
 #include <qtenvironmentvariables.h>
 #include <qtextstream.h>
+#include <qthread.h>
 #include <qtmetamacros.h>
+#include <sys/mman.h>
+#include <sys/sendfile.h>
 
-LogManager::LogManager(): colorLogs(qEnvironmentVariableIsEmpty("NO_COLOR")), stdoutStream(stdout) {
-	qInstallMessageHandler(&LogManager::messageHandler);
-}
+#include "paths.hpp"
+
+Q_LOGGING_CATEGORY(logLogging, "quickshell.logging", QtWarningMsg);
+
+LogManager::LogManager()
+    : colorLogs(qEnvironmentVariableIsEmpty("NO_COLOR"))
+    , stdoutStream(stdout) {}
 
 void LogManager::messageHandler(
     QtMsgType type,
@@ -32,6 +43,27 @@ LogManager* LogManager::instance() {
 	return instance;
 }
 
+void LogManager::init() {
+	auto* instance = LogManager::instance();
+
+	qInstallMessageHandler(&LogManager::messageHandler);
+
+	qCDebug(logLogging) << "Creating offthread logger...";
+	auto* thread = new QThread();
+	instance->threadProxy.moveToThread(thread);
+	thread->start();
+	QMetaObject::invokeMethod(&instance->threadProxy, "initInThread", Qt::BlockingQueuedConnection);
+	qCDebug(logLogging) << "Logger initialized.";
+}
+
+void LogManager::initFs() {
+	QMetaObject::invokeMethod(
+	    &LogManager::instance()->threadProxy,
+	    "initFs",
+	    Qt::BlockingQueuedConnection
+	);
+}
+
 void LogManager::formatMessage(
     QTextStream& stream,
     const LogMessage& msg,
@@ -75,3 +107,88 @@ void LogManager::formatMessage(
 
 	if (color && msg.type == QtFatalMsg) stream << "\033[0m";
 }
+
+void LoggingThreadProxy::initInThread() {
+	this->logging = new ThreadLogging(this);
+	this->logging->init();
+}
+
+void LoggingThreadProxy::initFs() { this->logging->initFs(); }
+
+void ThreadLogging::init() {
+	auto mfd = memfd_create("quickshell:logs", 0);
+
+	if (mfd == -1) {
+		qCCritical(logLogging) << "Failed to create memfd for initial log storage"
+		                       << qt_error_string(-1);
+		return;
+	}
+
+	this->file = new QFile();
+	this->file->open(mfd, QFile::WriteOnly, QFile::AutoCloseHandle);
+	this->fileStream.setDevice(this->file);
+
+	// This connection is direct so it works while the event loop is destroyed between
+	// QCoreApplication delete and Q(Gui)Application launch.
+	QObject::connect(
+	    LogManager::instance(),
+	    &LogManager::logMessage,
+	    this,
+	    &ThreadLogging::onMessage,
+	    Qt::DirectConnection
+	);
+
+	qCDebug(logLogging) << "Created memfd" << mfd << "for early logs.";
+}
+
+void ThreadLogging::initFs() {
+
+	qCDebug(logLogging) << "Starting filesystem logging...";
+	auto* runDir = QsPaths::instance()->instanceRunDir();
+
+	if (!runDir) {
+		qCCritical(logLogging
+		) << "Could not start filesystem logging as the runtime directory could not be created.";
+		return;
+	}
+
+	auto path = runDir->filePath("log.log");
+	auto* file = new QFile(path);
+
+	if (!file->open(QFile::WriteOnly | QFile::Truncate)) {
+		qCCritical(logLogging
+		) << "Could not start filesystem logger as the log file could not be created:"
+		  << path;
+		return;
+	}
+
+	qCDebug(logLogging) << "Copying memfd logs to log file...";
+
+	auto* oldFile = this->file;
+	oldFile->seek(0);
+	sendfile(file->handle(), oldFile->handle(), nullptr, oldFile->size());
+	this->file = file;
+	this->fileStream.setDevice(file);
+	delete oldFile;
+
+	qCDebug(logLogging) << "Switched logging to disk logs.";
+
+	auto* logManager = LogManager::instance();
+	QObject::disconnect(logManager, &LogManager::logMessage, this, &ThreadLogging::onMessage);
+
+	QObject::connect(
+	    logManager,
+	    &LogManager::logMessage,
+	    this,
+	    &ThreadLogging::onMessage,
+	    Qt::QueuedConnection
+	);
+
+	qCDebug(logLogging) << "Switched threaded logger to queued eventloop connection.";
+}
+
+void ThreadLogging::onMessage(const LogMessage& msg) {
+	if (this->fileStream.device() == nullptr) return;
+	LogManager::formatMessage(this->fileStream, msg, false, true);
+	this->fileStream << Qt::endl;
+}

src/core/logging.hpp

@@ -3,6 +3,7 @@
 #include <utility>
 
 #include <qdatetime.h>
+#include <qfile.h>
 #include <qlogging.h>
 #include <qobject.h>
 #include <qtextstream.h>
@@ -26,10 +27,44 @@ struct LogMessage {
 	QByteArray body;
 };
 
+class ThreadLogging: public QObject {
+	Q_OBJECT;
+
+public:
+	explicit ThreadLogging(QObject* parent): QObject(parent) {}
+
+	void init();
+	void initFs();
+	void setupFileLogging();
+
+private slots:
+	void onMessage(const LogMessage& msg);
+
+private:
+	QFile* file = nullptr;
+	QTextStream fileStream;
+};
+
+class LoggingThreadProxy: public QObject {
+	Q_OBJECT;
+
+public:
+	explicit LoggingThreadProxy() = default;
+
+public slots:
+	void initInThread();
+	void initFs();
+
+private:
+	ThreadLogging* logging = nullptr;
+};
+
 class LogManager: public QObject {
 	Q_OBJECT;
 
 public:
+	static void init();
+	static void initFs();
 	static LogManager* instance();
 
 	static void formatMessage(QTextStream& stream, const LogMessage& msg, bool color, bool timestamp);
@@ -43,4 +78,5 @@ private:
 
 	bool colorLogs;
 	QTextStream stdoutStream;
+	LoggingThreadProxy threadProxy;
 };

src/core/main.cpp

@@ -22,14 +22,12 @@
 #include <qtextstream.h>
 #include <qtpreprocessorsupport.h>
 
-#include "filelogger.hpp"
 #include "logging.hpp"
 #include "paths.hpp"
 #include "plugin.hpp"
 #include "rootwrapper.hpp"
 
 int qs_main(int argc, char** argv) {
-	LogManager::instance();
 	QString configFilePath;
 	QString workingDirectory;
 
@@ -48,6 +46,9 @@ int qs_main(int argc, char** argv) {
 		QCoreApplication::setApplicationName("quickshell");
 		QCoreApplication::setApplicationVersion("0.1.0 (" GIT_REVISION ")");
 
+		// Start log manager - has to happen with an active event loop or offthread can't be started.
+		LogManager::init();
+
 		QCommandLineParser parser;
 		parser.addHelpOption();
 		parser.addVersionOption();
@@ -390,7 +391,7 @@ int qs_main(int argc, char** argv) {
 		app = new QGuiApplication(argc, argv);
 	}
 
-	FileLoggerThread::init();
+	LogManager::initFs();
 
 	if (debugPort != -1) {
 		QQmlDebuggingEnabler::enableDebugging(true);

src/core/paths.cpp

@@ -21,7 +21,6 @@ void QsPaths::init(QString shellId) { QsPaths::instance()->shellId = std::move(s
 QDir* QsPaths::cacheDir() {
 	if (this->cacheState == DirState::Unknown) {
 		auto dir = QDir(QStandardPaths::writableLocation(QStandardPaths::CacheLocation));
-		dir = QDir(dir.filePath("quickshell"));
 		dir = QDir(dir.filePath(this->shellId));
 		this->mCacheDir = dir;