refactor: Refactor config reader & config API

src/common/CMakeLists.txt

@@ -1,7 +1,6 @@
 configure_file("Constants.h.in" "Constants.h" IMMEDIATE @ONLY)
 set(PUBLIC_HEADERS
-    ${CMAKE_SOURCE_DIR}/src/common/ConfigReader.h
-    ${CMAKE_SOURCE_DIR}/src/common/Configuration.h
+    ${CMAKE_SOURCE_DIR}/src/common/Config.h
     ${CMAKE_SOURCE_DIR}/src/common/MessageHandler.h
     ${CMAKE_SOURCE_DIR}/src/common/Messages.h
     ${CMAKE_SOURCE_DIR}/src/common/Session.h
@@ -13,8 +12,6 @@ set(PUBLIC_HEADERS
 )
 
 set(SRCS
-    ${CMAKE_SOURCE_DIR}/src/common/ConfigReader.cpp
-    ${CMAKE_SOURCE_DIR}/src/common/Configuration.cpp
     ${CMAKE_SOURCE_DIR}/src/common/Session.cpp
     ${CMAKE_SOURCE_DIR}/src/common/SignalHandler.cpp
     ${CMAKE_SOURCE_DIR}/src/common/SocketWriter.cpp

src/common/Config.h

@@ -0,0 +1,283 @@
+// Copyright (C) 2026 UnionTech Software Technology Co., Ltd.
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <QFile>
+#include <QMap>
+#include <QObject>
+#include <QPair>
+#include <QVariant>
+
+#include "Constants.h"
+
+namespace DDM {
+    class Config : public QObject {
+        Q_OBJECT
+    public:
+        /**
+         * Constructor.
+         *
+         * @param configPath Path to the configuration file.
+         * @param defaults Default configuration values and descriptions.
+         * @param parent Parent QObject.
+         */
+        Config(const QString &configPath,
+               //   section       entry          default   description
+               QMap<QString, QMap<QString, QPair<QVariant, QString>>> defaults = {},
+               QObject *parent = nullptr)
+            : QObject(parent)
+            , m_configPath(configPath)
+            , m_defaults(defaults) { }
+
+        /**
+         * Get a configuration entry value.
+         * If the entry is not found in the loaded configuration, the default value is returned.
+         * If no default value is set, an exception is thrown.
+         *
+         * @param section The configuration section name.
+         * @param entry The configuration entry name.
+         * @return The value of the configuration entry.
+         */
+        template<typename T>
+        inline T get(const QString &section, const QString &entry) const {
+            if (m_data.contains(section) && m_data[section].contains(entry))
+                return m_data[section][entry].value<T>();
+            else if (m_defaults.contains(section) && m_defaults[section].contains(entry))
+                return m_defaults[section][entry].first.value<T>();
+            else
+                throw std::runtime_error(QStringLiteral("Config entry '%1/%2' not found")
+                                             .arg(section, entry)
+                                             .toStdString());
+        }
+
+        /**
+         * Get a configuration entry value inside the default section.
+         * If the entry is not found in the loaded configuration, the default value is returned.
+         * If no default value is set, an exception is thrown.
+         *
+         * @param entry The configuration entry name.
+         * @return The value of the configuration entry.
+         */
+        template<typename T>
+        inline T get(const QString &entry) const {
+            return get<T>({}, entry);
+        }
+
+        /**
+         * Set a configuration entry value.
+         *
+         * @param section The configuration section name.
+         * @param entry The configuration entry name.
+         * @param value The value to set.
+         */
+        template<typename T>
+        inline void set(const QString &section, const QString &entry, const T &value) {
+            m_data[section][entry] = QVariant::fromValue(value);
+        }
+
+        /**
+         * Set a configuration entry value inside the default section.
+         *
+         * @param entry The configuration entry name.
+         * @param value The value to set.
+         */
+        template<typename T>
+        inline void set(const QString &entry, const T &value) {
+            m_data[{}][entry] = QVariant::fromValue(value);
+        }
+
+        /**
+         * Reset a configuration entry to its default value.
+         *
+         * @param section The configuration section name.
+         * @param entry The configuration entry name.
+         * @return True if the entry was reset, false if it was not found or already default.
+         */
+        inline bool setDefault(const QString &section, const QString &entry) {
+            if (m_data.contains(section) && m_data[section].contains(entry)) {
+                m_data[section].remove(entry);
+                return true;
+            }
+            return false;
+        }
+
+        /**
+         * Reset a configuration entry to its default value inside the default section.
+         *
+         * @param entry The configuration entry name.
+         * @return True if the entry was reset, false if it was not found or already default.
+         */
+        inline bool setDefault(const QString &entry) {
+            return setDefault({}, entry);
+        }
+
+        /**
+         * Load the configuration from the file.
+         *
+         * @return True if the configuration was loaded successfully, false otherwise.
+         */
+        bool load() {
+            QFile file(m_configPath);
+            if (!file.open(QIODevice::ReadOnly)) {
+                return false;
+            }
+            QString currentSection{};
+            while (!file.atEnd()) {
+                QString line = QString::fromLocal8Bit(file.readLine()).trimmed();
+                if (line.isEmpty() || line.startsWith('#'))
+                    continue;
+                if (line.startsWith('[') && line.endsWith(']')) {
+                    currentSection = line.mid(1, line.length() - 2).trimmed();
+                } else {
+                    int separatorPosition = line.indexOf('=');
+                    if (separatorPosition >= 0) {
+                        if (!m_data.contains(currentSection))
+                            m_data[currentSection] = {};
+                        QString name = line.left(separatorPosition).trimmed();
+                        QString value = line.mid(separatorPosition + 1).trimmed();
+                        if (value.isEmpty()) {
+                            m_data[currentSection][name] = QVariant();
+                        } else if (value.indexOf(',') >= 0) {
+                            QStringList list = value.split(',', Qt::SkipEmptyParts);
+                            for (QString &item : list)
+                                item = item.trimmed();
+                            m_data[currentSection][name] = QVariant(list);
+                        } else
+                            m_data[currentSection][name] = QVariant(value);
+                    }
+                }
+            }
+            return true;
+        }
+
+        /**
+         * Save the configuration to the file.
+         *
+         * @return True if the configuration was saved successfully, false otherwise.
+         */
+        bool save() const {
+            QFile file(m_configPath);
+            if (!file.open(QIODevice::WriteOnly | QIODevice::Truncate)) {
+                return false;
+            }
+            QTextStream out(&file);
+            for (auto section = m_data.cbegin(); section != m_data.cend(); ++section) {
+                const QString &sectionName = section.key();
+                if (!sectionName.isEmpty())
+                    out << "[" << sectionName << "]\n";
+                const auto &entries = section.value();
+                for (auto entry = entries.constBegin(); entry != entries.constEnd(); ++entry) {
+                    if (entry.value().userType() == QMetaType::QStringList)
+                        out << entry.key() << "=" << entry.value().toStringList().join(", ") << "\n";
+                    else
+                        out << entry.key() << "=" << entry.value().toString() << "\n";
+                }
+                out << "\n";
+            }
+            return true;
+        }
+
+        /**
+         * Serialize the default configuration to the format of the
+         * configuration file, as a string.
+         *
+         * @return The default configuration as a string.
+         */
+        QString defaultConfig() const {
+            QString str;
+            QTextStream out(&str);
+            for (auto section = m_defaults.cbegin(); section != m_defaults.cend(); ++section) {
+                const QString &sectionName = section.key();
+                if (!sectionName.isEmpty())
+                    out << "[" << sectionName << "]\n\n";
+                const auto &entries = section.value();
+                for (auto entry = entries.constBegin(); entry != entries.constEnd(); ++entry) {
+                    const QString &description = entry.value().second;
+                    if (!description.isEmpty())
+                        for (const QString &line : description.split('\n'))
+                            out << "# " << line << "\n";
+                    if (entry.value().first.userType() == QMetaType::QStringList)
+                        out << entry.key() << "=" << entry.value().first.toStringList().join(", ") << "\n\n";
+                    else
+                        out << entry.key() << "=" << entry.value().first.toString() << "\n\n";
+                }
+            }
+            return str;
+        }
+
+        /**
+         * Wipe all loaded configuration data, reset all entries to default.
+         */
+        inline void wipe() {
+            m_data.clear();
+        }
+
+    private:
+        /** Path to the configuration file. */
+        QString m_configPath{};
+        //   section       entry    value
+        QMap<QString, QMap<QString, QVariant>> m_data;
+        //   section       entry          default   description
+        QMap<QString, QMap<QString, QPair<QVariant, QString>>> m_defaults;
+    };
+
+    /** Main configuration instance. */
+    inline Config mainConfig(
+        CONFIG_FILE,
+        { { {},
+            { { "HaltCommand", { HALT_COMMAND, "Halt command" } },
+              { "RebootCommand", { REBOOT_COMMAND, "Reboot command" } },
+              { "Namespaces",
+                { QStringList(),
+                  "List of Linux namespaces for user session to enter" } } } },
+          { "Theme",
+            { { "CursorTheme", { QString(), "Cursor theme used in the greeter" } },
+              { "CursorSize", { QString(), "Cursor size used in the greeter" } } } },
+          { "X11",
+            { { "ServerPath", { "/usr/bin/X", "Path to X server binary" } },
+              { "ServerArguments",
+                { "-nolisten tcp", "Arguments passed to the X server invocation" } },
+              { "SessionDir",
+                { QStringList{ "/usr/local/share/xsessions", "/usr/share/xsessions" },
+                  "Comma-separated list of directories containing available X sessions" } },
+              { "SessionCommand",
+                { SESSION_COMMAND,
+                  "Path to a script to execute when starting the desktop session" } },
+              { "SessionLogFile",
+                { ".local/share/ddm/xorg-session.log", "Path to the user session log file" } },
+              { "DisplayCommand",
+                { QStringLiteral(DATA_INSTALL_DIR "/scripts/Xsetup"),
+                  "Path to a script to execute when starting the display server" } },
+              { "DisplayStopCommand",
+                { QStringLiteral(DATA_INSTALL_DIR "/scripts/Xstop"),
+                  "Path to a script to execute when stopping the display server" } } } },
+          { "Wayland",
+            { { "SessionDir",
+                { QStringList{ "/usr/local/share/wayland-sessions", "/usr/share/wayland-sessions" },
+                  "Comma-separated list of directories containing available Wayland sessions" } },
+              { "SessionCommand",
+                { WAYLAND_SESSION_COMMAND,
+                  "Path to a script to execute when starting the desktop session" } },
+              { "SessionLogFile",
+                { ".local/share/ddm/wayland-session.log",
+                  "Path to the user session log file" } } } },
+          { "Single",
+            { { "SessionCommand",
+                { WAYLAND_SESSION_COMMAND,
+                  "Path to a script to execute when starting the desktop session" } } } },
+          { "Users",
+            { { "DefaultPath",
+                { "/usr/local/bin:/usr/bin:/bin", "Default $PATH for logged in users" } },
+              { "RememberLastUser", { true, "Remember the last successfully logged in user" } },
+              { "RememberLastSession",
+                { true, "Remember the session of the last successfully logged in user" } } } } });
+
+    /** State configuration instance. */
+    inline Config stateConfig(
+        QStringLiteral(STATE_DIR "/state.conf"),
+        { { "Last",
+            { { "User", { QString(), "The last successfully logged in user" } },
+              { "Session",
+                { QString(), "The session of the last successfully logged in user" } } } } });
+} // namespace DDM