feat: implement AppImage auto-updater for Linux

src/common/utility.h

@@ -170,6 +170,10 @@ namespace Utility {
     constexpr bool isBSD(); // use with care, does not match OS X
 
     OCSYNC_EXPORT QString platformName();
+
+    // AppImage helpers (Linux only, return empty/false elsewhere)
+    OCSYNC_EXPORT QString appImagePath();
+    OCSYNC_EXPORT bool isRunningInAppImage();
     // crash helper for --debug
     OCSYNC_EXPORT void crash();
 

src/common/utility_mac.mm

@@ -18,6 +18,16 @@
 
 namespace OCC {
 
+QString Utility::appImagePath()
+{
+    return {};
+}
+
+bool Utility::isRunningInAppImage()
+{
+    return false;
+}
+
 QVector<Utility::ProcessInfosForOpenFile> Utility::queryProcessInfosKeepingFileOpen(const QString &filePath)
 {
     Q_UNUSED(filePath)

src/common/utility_unix.cpp

@@ -18,6 +18,17 @@
 
 namespace OCC {
 
+QString Utility::appImagePath()
+{
+    return qEnvironmentVariable("APPIMAGE");
+}
+
+bool Utility::isRunningInAppImage()
+{
+    const auto currentAppImagePath = appImagePath();
+    return !currentAppImagePath.isEmpty() && QFile::exists(currentAppImagePath);
+}
+
 QVector<Utility::ProcessInfosForOpenFile> Utility::queryProcessInfosKeepingFileOpen(const QString &filePath)
 {
     Q_UNUSED(filePath)
@@ -99,9 +110,9 @@ void Utility::setLaunchOnStartup(const QString &appName, const QString &guiName,
         }
         // When running inside an AppImage, we need to set the path to the
         // AppImage instead of the path to the executable
-        const QString appImagePath = qEnvironmentVariable("APPIMAGE");
-        const bool runningInsideAppImage = !appImagePath.isNull() && QFile::exists(appImagePath);
-        const QString executablePath = runningInsideAppImage ? appImagePath : QCoreApplication::applicationFilePath();
+        const auto currentAppImagePath = appImagePath();
+        const auto runningInsideAppImage = isRunningInAppImage();
+        const auto executablePath = runningInsideAppImage ? currentAppImagePath : QCoreApplication::applicationFilePath();
 
         QTextStream ts(&iniFile);
         ts << QLatin1String("[Desktop Entry]\n")
@@ -134,10 +145,7 @@ QString Utility::getCurrentUserName()
 
 void Utility::registerUriHandlerForLocalEditing()
 {
-    const auto appImagePath = qEnvironmentVariable("APPIMAGE");
-    const auto runningInsideAppImage = !appImagePath.isNull() && QFile::exists(appImagePath);
-
-    if (!runningInsideAppImage) {
+    if (!isRunningInAppImage()) {
         // only register x-scheme-handler if running inside appImage
         return;
     }

src/common/utility_win.cpp

@@ -34,6 +34,16 @@ static const char runPathC[] = R"(HKEY_CURRENT_USER\Software\Microsoft\Windows\C
 
 namespace OCC {
 
+QString Utility::appImagePath()
+{
+    return {};
+}
+
+bool Utility::isRunningInAppImage()
+{
+    return false;
+}
+
 QVector<Utility::ProcessInfosForOpenFile> Utility::queryProcessInfosKeepingFileOpen(const QString &filePath)
 {
     QVector<ProcessInfosForOpenFile> results;

src/gui/CMakeLists.txt

@@ -285,6 +285,13 @@ IF(BUILD_UPDATER)
         updater/updater.h
         updater/updater.cpp
     )
+    # Linux AppImage updater
+    if(UNIX AND NOT APPLE)
+        list(APPEND updater_SRCS
+            updater/appimageupdater.h
+            updater/appimageupdater.cpp
+        )
+    endif()
 endif()
 
 IF( APPLE )