Reimplement ArgumentParser in C++

Makes it possible to use --help and --version even if another instance
of Moment is already running. Fixes #122.

src/gui/ArgumentParser.qml

@@ -1,59 +0,0 @@
-// Copyright Mirage authors & contributors <https://github.com/mirukana/mirage>
-// and Moment contributors <https://gitlab.com/mx-moment/moment>
-// SPDX-License-Identifier: LGPL-3.0-or-later
-
-pragma Singleton
-import QtQuick 2.12
-
-QtObject {
-
-    property bool startInTray: false
-    property string loadQml: ""
-
-    readonly property string help: `Usage: ${Qt.application.name} [options]
-
-    Options:
-        -t, --start-in-tray  Start in the system tray, without a visible window
-        -l, --load-qml PATH  Override the file to be loaded as src/gui/UI.qml
-        -V, --version        Show the application's version and exit
-        -h, --help           Show this help and exit
-
-    Environment variables:
-        MOMENT_CONFIG_DIR  Override the default configuration folder
-        MOMENT_DATA_DIR    Override the default application data folder
-        MOMENT_CACHE_DIR   Override the default cache and downloads folder
-        http_proxy         Override the General.proxy setting, see settings.py
-    `
-
-    readonly property bool ready: {
-        const passedArguments = Qt.application.arguments.slice(1)
-
-        while (passedArguments.length) {
-            switch (passedArguments.shift()) {
-                case "-h":
-                case "--help":
-                    print("\n\n" + help.replace(/^ {4}/gm, ""))
-                    Qt.quit()
-                    break
-
-                case "-v":
-                case "--version":
-                    print(Qt.application.version)
-                    Qt.quit()
-                    break
-
-                case "-t":
-                case "--start-in-tray":
-                    startInTray = true
-                    break
-
-                case "-l":
-                case "--load-qml":
-                    loadQml = passedArguments.shift()
-                    break
-            }
-        }
-
-        return true
-    }
-}

src/gui/Window.qml

@@ -28,6 +28,8 @@ ApplicationWindow {
     property var theme: null
     property var themeRules: null
     property string settingsFolder
+    property bool startInTray
+    property string loadQml
 
     readonly property var visibleMenus: ({})
     readonly property var visiblePopups: ({})
@@ -98,7 +100,7 @@ ApplicationWindow {
     minimumHeight: theme ? theme.minimumSupportedHeight : 120
     width: Math.min(screen.width, 1152)
     height: Math.min(screen.height, 768)
-    visible: ArgumentParser.ready && ! ArgumentParser.startInTray
+    visible: ! startInTray
     color: "transparent"
 
     onClosing: if (py.ready && settings.General.close_to_tray) {
@@ -123,8 +125,8 @@ ApplicationWindow {
         focus: true
         scale: py.ready ? 1 : 0.5
         source:
-            ArgumentParser.ready && py.ready ?
-            (ArgumentParser.loadQml || "UI.qml") :
+            py.ready ?
+            (loadQml || "UI.qml") :
             ""
 
         Behavior on scale { HNumberAnimation { overshoot: 3; factor: 1.2 } }

src/gui/qmldir

@@ -1,2 +1 @@
 singleton ModelStore 0.1 ModelStore.qml
-singleton ArgumentParser 0.1 ArgumentParser.qml

src/main.cpp

@@ -19,6 +19,8 @@
 #include <QFile>
 #include <QLockFile>
 #include <QMessageBox>
+#include <QCommandLineParser>
+#include <iostream>
 #include <signal.h>
 
 #ifdef Q_OS_UNIX
@@ -372,6 +374,38 @@ int main(int argc, char *argv[]) {
     // because migrate displays a popup dialog
     QApplication app(argc, argv);
 
+    QCommandLineParser args;
+
+    QCommandLineOption startInTrayOption(QStringList() << "t" << "start-in-tray",
+            "Start in the system tray, without a visible window.");
+    args.addOption(startInTrayOption);
+
+    QCommandLineOption loadQmlOption(QStringList() << "l" << "load-qml",
+            "Override the file to be loaded as src/gui/UI.qml", "PATH");
+    args.addOption(loadQmlOption);
+
+    QCommandLineOption helpOption(QStringList() << "h" << "help",
+            "Displays help on commandline options.");
+    args.addOption(helpOption);
+
+    args.addVersionOption();
+
+    args.process(app);
+
+    if (args.isSet(helpOption)) {
+        std::cout << args.helpText().toStdString() << std::endl
+            << "Environment variables:" << std::endl
+            << "  MOMENT_CONFIG_DIR  Override the configuration folder"
+            << std::endl
+            << "  MOMENT_DATA_DIR    Override the application data folder"
+            << std::endl
+            << "  MOMENT_CACHE_DIR   Override the cache and downloads folder"
+            << std::endl
+            << "  http_proxy         Override the General.proxy setting, see "
+            << "settings.py" << std::endl;
+        exit(EXIT_SUCCESS);
+    }
+
     if (shouldMigrateFromMirage()) tryMigrateFromMirage();
 
     QString customConfigDir(qEnvironmentVariable("MOMENT_CONFIG_DIR"));
@@ -489,7 +523,10 @@ int main(int argc, char *argv[]) {
         app.exit(EXIT_FAILURE);
     }
 
-    component.create(objectContext)->setProperty("settingsFolder", "file://"+settingsFolder);
+    QObject *comp = component.create(objectContext);
+    comp->setProperty("settingsFolder", "file://"+settingsFolder);
+    comp->setProperty("startInTray",    args.isSet(startInTrayOption));
+    comp->setProperty("loadQml",        args.value(loadQmlOption));
 
     // Finally, execute the app. Return its exit code after clearing the lock.
     int exit_code = app.exec();