projectexplorer: add availableQmlPreviewTranslations()

Preparation for a test translations feature.

Change-Id: I1a7ccecab803f5838cd765b7dca99bcf5bb9e8a1
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/projectexplorer/project.cpp

@@ -983,6 +983,21 @@ QVariant Project::extraData(const QString &key) const
     return d->m_extraData.value(key);
 }
 
+QStringList Project::availableQmlPreviewTranslations(QString *errorMessage)
+{
+    const auto projectDirectory = rootProjectDirectory().toFileInfo().absoluteFilePath();
+    const QDir languageDirectory(projectDirectory + "/i18n");
+    const auto qmFiles = languageDirectory.entryList({"qml_*.qm"});
+    if (qmFiles.isEmpty() && errorMessage)
+        errorMessage->append(tr("Could not find any qml_*.qm file at '%1'").arg(languageDirectory.absolutePath()));
+    return Utils::transform(qmFiles, [](const QString &qmFile) {
+        const int localeStartPosition = qmFile.lastIndexOf("_") + 1;
+        const int localeEndPosition = qmFile.size() - QString(".qm").size();
+        const QString locale = qmFile.left(localeEndPosition).mid(localeStartPosition);
+        return locale;
+    });
+}
+
 #if defined(WITH_TESTS)
 
 } // namespace ProjectExplorer

src/plugins/projectexplorer/project.h

@@ -173,6 +173,8 @@ public:
     void setExtraData(const QString &key, const QVariant &data);
     QVariant extraData(const QString &key) const;
 
+    QStringList availableQmlPreviewTranslations(QString *errorMessage);
+
 signals:
     void projectFileIsDirty(const Utils::FilePath &path);
 

src/plugins/qmldesigner/qmlpreviewplugin/qmlpreviewactions.cpp

@@ -221,15 +221,21 @@ SwitchLanguageComboboxAction::SwitchLanguageComboboxAction(QObject *parent)
 QWidget *SwitchLanguageComboboxAction::createWidget(QWidget *parent)
 {
     QPointer<QComboBox> comboBox = new QComboBox(parent);
-    comboBox->setToolTip(tr("Switch the language used by preview."));
+    const QString toolTip(tr("Switch the language used by preview."));
+    comboBox->setToolTip(toolTip);
     comboBox->addItem(tr("Default"));
 
-    auto refreshComboBoxFunction = [this, comboBox] (ProjectExplorer::Project *project) {
+    auto refreshComboBoxFunction = [this, comboBox, toolTip] (ProjectExplorer::Project *project) {
         if (comboBox) {
-            if (updateProjectLocales(project)) {
+            QString errorMessage;
+            auto locales = project->availableQmlPreviewTranslations(&errorMessage);
+            if (!errorMessage.isEmpty())
+                comboBox->setToolTip(QString("%1<br/>(%2)").arg(toolTip, errorMessage));
+            if (m_previousLocales != locales) {
                 comboBox->clear();
                 comboBox->addItem(tr("Default"));
-                comboBox->addItems(m_localeStrings);
+                comboBox->addItems(locales);
+                m_previousLocales = locales;
             }
         }
     };
@@ -250,24 +256,6 @@ QWidget *SwitchLanguageComboboxAction::createWidget(QWidget *parent)
     return comboBox;
 }
 
-bool SwitchLanguageComboboxAction::updateProjectLocales(Project *project)
-{
-    if (!project)
-        return false;
-    auto previousLocales = m_localeStrings;
-    m_localeStrings.clear();
-    const auto projectDirectory = project->rootProjectDirectory().toFileInfo().absoluteFilePath();
-    const QDir languageDirectory(projectDirectory + "/i18n");
-    const auto qmFiles = languageDirectory.entryList({"qml_*.qm"});
-    m_localeStrings = Utils::transform(qmFiles, [](const QString &qmFile) {
-        const int localeStartPosition = qmFile.lastIndexOf("_") + 1;
-        const int localeEndPosition = qmFile.size() - QString(".qm").size();
-        const QString locale = qmFile.left(localeEndPosition).mid(localeStartPosition);
-        return locale;
-    });
-    return previousLocales != m_localeStrings;
-}
-
 SwitchLanguageAction::SwitchLanguageAction()
     : m_switchLanguageAction(new SwitchLanguageComboboxAction(nullptr))
 {

src/plugins/qmldesigner/qmlpreviewplugin/qmlpreviewactions.h

@@ -113,8 +113,7 @@ signals:
 protected:
     QWidget *createWidget(QWidget *parent) override;
 private:
-    bool updateProjectLocales(ProjectExplorer::Project *project);
+    QStringList m_previousLocales;
-    QStringList m_localeStrings;
 };
 
 class SwitchLanguageAction : public ActionInterface