Make QCoreApplication::applicationName() default to argv[0]

This makes it more useful in all the Qt apps that don't set it,
given that it's used internally by QTemporaryFile, QTemporaryDir,
QStandardPaths, QDBus, QAccessibleApplication, etc.

Qt4 compatibility in the deprecated QDesktopServices is preserved,
no fallback there.

Change-Id: I584463507cf917a3720793c6bd45d07c60f8356c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 18 insertions, 9 deletions

diff --git a/src/gui/util/qdesktopservices.cpp b/src/gui/util/qdesktopservices.cpp
index 1a6661440c..26aecadcf4 100644
--- a/src/gui/util/qdesktopservices.cpp
+++ b/src/gui/util/qdesktopservices.cpp
@@ -287,17 +287,26 @@ void QDesktopServices::unsetUrlHandler(const QString &scheme)
 
 QString QDesktopServices::storageLocationImpl(StandardLocation type)
 {
-#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
     if (type == DataLocation) {
-        QString xdgDataHome = QLatin1String(qgetenv("XDG_DATA_HOME"));
-        if (xdgDataHome.isEmpty())
-            xdgDataHome = QDir::homePath() + QLatin1String("/.local/share");
-        xdgDataHome += QLatin1String("/data/")
-                    + QCoreApplication::organizationName() + QLatin1Char('/')
-                    + QCoreApplication::applicationName();
-        return xdgDataHome;
-    }
+        // Preserve Qt 4 compatibility:
+        // * QCoreApplication::applicationName() must default to empty
+        // * Unix data location is under the "data/" subdirectory
+        extern Q_CORE_EXPORT QString qt_applicationName_noFallback();
+        const QString compatAppName = qt_applicationName_noFallback();
+        const QString baseDir = QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation);
+#if defined(Q_OS_WIN) || defined(Q_OS_MAC)
+        QString result = baseDir;
+        if (!QCoreApplication::organizationName().isEmpty())
+            result += QLatin1Char('/') + QCoreApplication::organizationName();
+        if (!compatAppName.isEmpty())
+            result += QLatin1Char('/') + compatAppName;
+        return result;
+#elif defined(Q_OS_UNIX)
+        return baseDir + QLatin1String("/data/")
+            + QCoreApplication::organizationName() + QLatin1Char('/')
+            + compatAppName;
 #endif
+    }
     return QStandardPaths::writableLocation(static_cast<QStandardPaths::StandardLocation>(type));
 }