add file+dir watcher & gatekeep reloads

Plugins/ZShell/Config/config.cpp

@@ -24,6 +24,12 @@
 #include <QDir>
 #include <QDebug>
 #include <QFutureWatcher>
+#include <QFileInfo>
+#include <QFileSystemWatcher>
+#include <qcontainerfwd.h>
+#include <qfileinfo.h>
+#include <qfilesystemwatcher.h>
+#include <qthreadpool.h>
 
 namespace ZShell::config {
 
@@ -51,7 +57,25 @@ Config::Config(QObject* parent)
 	m_saveTimer.setInterval(300);
 	connect(&m_saveTimer, &QTimer::timeout, this, &Config::flushAsync);
 
+	m_reloadTimer.setSingleShot(true);
+	m_reloadTimer.setInterval(50);
+	connect(&m_reloadTimer, &QTimer::timeout, this, &Config::reloadAsync);
+
+	connect(
+		&m_watcher,
+		&QFileSystemWatcher::directoryChanged,
+		this,
+		&Config::onWatcherEvent);
+
+	connect(
+		&m_watcher,
+		&QFileSystemWatcher::fileChanged,
+		this,
+		&Config::onWatcherEvent);
+
 	loadSync();
+	updateWatch();
+
 	m_firstLoadDone = true;
 }
 
@@ -80,33 +104,84 @@ void Config::loadSync() {
 	m_loading = false;
 }
 
+void Config::updateWatch() {
+	const QFileInfo info(filePath());
+
+	const QString dir = info.absolutePath();
+	const QString file = info.absoluteFilePath();
+
+	if (!m_watcher.directories().contains(dir)) m_watcher.addPath(dir);
+	if (info.exists() && !m_watcher.files().contains(file))
+		m_watcher.addPath(file);
+}
+
+void Config::onWatcherEvent(const QString&) {
+	updateWatch();
+
+	const QFileInfo info(filePath());
+	if (!info.exists()) return;
+
+	QFile file(info.absoluteFilePath());
+	if (!file.open(QIODevice::ReadOnly)) return;
+
+	const QByteArray hash =
+		QCryptographicHash::hash(file.readAll(), QCryptographicHash::Sha256);
+
+	{
+		QMutexLocker lock(&m_writeMutex);
+
+		if (hash == m_lastWriteHash) return;
+	}
+
+	m_reloadPending = true;
+
+	if (!m_loading) m_reloadTimer.start();
+}
+
 void Config::loadAsync() {
 	m_loading = true;
+
 	auto future = QtConcurrent::run([this]() {
 		QFile f(filePath());
+
 		if (f.open(QIODevice::ReadOnly)) {
 			const auto doc = QJsonDocument::fromJson(f.readAll());
+
 			if (doc.isObject()) {
 				QMetaObject::invokeMethod(
 					this,
 					[this, doc]() {
 						loadFromJson(QJsonValue(doc.object()));
 						m_loading = false;
+
+						if (m_reloadPending) m_reloadTimer.start();
 					},
 					Qt::QueuedConnection);
 			} else {
 				QMetaObject::invokeMethod(
 					this,
-					[this]() { m_loading = false; },
+					[this]() {
+						m_loading = false;
+
+						if (m_reloadPending) m_reloadTimer.start();
+					},
 					Qt::QueuedConnection);
 			}
 		} else {
 			qInfo() << "Config: failed to reload from" << filePath()
 					<< "- using in-memory values";
+
 			QMetaObject::invokeMethod(
-				this, [this]() { m_loading = false; }, Qt::QueuedConnection);
+				this,
+				[this]() {
+					m_loading = false;
+
+					if (m_reloadPending) m_reloadTimer.start();
+				},
+				Qt::QueuedConnection);
 		}
 	});
+
 	m_loadFuture = future;
 }
 
@@ -119,6 +194,9 @@ void Config::load() {
 }
 
 void Config::reloadAsync() {
+	if (m_loading) return;
+
+	m_reloadPending = false;
 	loadAsync();
 }
 
@@ -128,10 +206,24 @@ void Config::scheduleSave() {
 }
 
 void Config::flushAsync() {
-	auto future = QtConcurrent::run([this]() {
-		const QByteArray data =
-			QJsonDocument(toJson().toObject()).toJson(QJsonDocument::Indented);
-		writeAtomically(data);
+	const QByteArray data =
+		QJsonDocument(toJson().toObject()).toJson(QJsonDocument::Indented);
+
+	const QByteArray hash =
+		QCryptographicHash::hash(data, QCryptographicHash::Sha256);
+
+	QThreadPool::globalInstance()->start([this, data, hash]() {
+		const bool success = writeAtomically(data);
+
+		QMetaObject::invokeMethod(
+			this,
+			[this, success, hash]() {
+				if (!success) return;
+
+				QMutexLocker lock(&m_writeMutex);
+				m_lastWriteHash = hash;
+			},
+			Qt::QueuedConnection);
 	});
 }
 
@@ -140,15 +232,26 @@ void Config::saveNow() {
 	flushAsync();
 }
 
-void Config::writeAtomically(const QByteArray& data) {
+bool Config::writeAtomically(const QByteArray& data) {
 	QSaveFile f(filePath());
+
 	if (!f.open(QIODevice::WriteOnly)) {
 		qWarning() << "Config: failed to open for atomic write:"
 				   << f.errorString();
-		return;
+		return false;
 	}
-	f.write(data);
-	if (!f.commit()) qWarning() << "Config: commit failed:" << f.errorString();
+
+	if (f.write(data) != data.size()) {
+		qWarning() << "Config: failed to write:" << f.errorString();
+		return false;
+	}
+
+	if (!f.commit()) {
+		qWarning() << "Config: commit failed:" << f.errorString();
+		return false;
+	}
+
+	return true;
 }
 
 }; // namespace ZShell::config

Plugins/ZShell/Config/config.hpp

@@ -1,11 +1,14 @@
 #pragma once
 
 #include "configobject.hpp"
-#include <qqmlregistration.h>
-#include <QTimer>
-#include <QtConcurrent/QtConcurrent>
+
+#include <QByteArray>
+#include <QFileSystemWatcher>
 #include <QFuture>
-#include <qtmetamacros.h>
+#include <QMutex>
+#include <QTimer>
+#include <qqmlregistration.h>
+#include <QtConcurrent/QtConcurrent>
 
 class QQmlEngine;
 class QJSEngine;
@@ -79,14 +82,23 @@ class Config : public ConfigObject {
 	private Q_SLOTS:
 	void scheduleSave();
 	void flushAsync();
+	void onWatcherEvent(const QString& path);
 
 	private:
 	QString filePath() const;
-	void writeAtomically(const QByteArray& data);
+	bool writeAtomically(const QByteArray& data);
+	void updateWatch();
 	void loadSync();
 	void loadAsync();
 
 	QTimer m_saveTimer;
+	QTimer m_reloadTimer;
+	QFileSystemWatcher m_watcher;
+
+	QMutex m_writeMutex;
+	QByteArray m_lastWriteHash;
+
+	bool m_reloadPending = false;
 	bool m_loading = false;
 	bool m_firstLoadDone = false;
 	QFuture<void> m_loadFuture;