Designer: Refactor save/load.

No longer pop up message boxes in QDesignerFormWindowInterface::
contents(), introduce QDesignerFormWindowInterface::checkContents()
instead that checks for orphaned top level spacers (use in
Designer application).

Give QDesignerFormWindowInterface::setContents() a bool return and
pass an optional error string back for IDE integrations.

Remove all Qt3 form conversion logic
from the loading logic (since there is no more uic3); do not
do any additional checks there since everything has been
moved to QAbstractFormBuilder::load() (including language).

Thus, QDesignerFormWindowInterface::setContents() no
longer pops up message boxes, either.

Dependent on: qtbase/449b8a93170ecc19f2f438b160d0bc4122999401

20 files changed, 98 insertions, 278 deletions

diff --git a/src/designer/src/components/formeditor/formwindow.cpp b/src/designer/src/components/formeditor/formwindow.cpp
index e39e36cee..1abf7cd71 100644
--- a/src/designer/src/components/formeditor/formwindow.cpp
+++ b/src/designer/src/components/formeditor/formwindow.cpp
@@ -2139,7 +2139,7 @@ bool FormWindow::handleContextMenu(QWidget *, QWidget *managedWidget, QContextMe
     return true;
 }
 
-void FormWindow::setContents(QIODevice *dev)
+bool FormWindow::setContents(QIODevice *dev, QString *errorMessageIn /* = 0 */)
 {
     UpdateBlocker ub(this);
     clearSelection();
@@ -2153,16 +2153,24 @@ void FormWindow::setContents(QIODevice *dev)
 
     QDesignerResource r(this);
     QWidget *w = r.load(dev, formContainer());
-    setMainContainer(w);
-    emit changed();
+    if (w) {
+        setMainContainer(w);
+        emit changed();
+    }
+    if (errorMessageIn)
+        *errorMessageIn = r.errorString();
+    return w != 0;
 }
 
-void FormWindow::setContents(const QString &contents)
+bool FormWindow::setContents(const QString &contents)
 {
+    QString errorMessage;
     QByteArray data = contents.toUtf8();
     QBuffer b(&data);
-    if (b.open(QIODevice::ReadOnly))
-        setContents(&b);
+    const bool success = b.open(QIODevice::ReadOnly) &&  setContents(&b, &errorMessage);
+    if (!success && !errorMessage.isEmpty())
+        designerWarning(errorMessage);
+    return success;
 }
 
 void FormWindow::layoutContainer(QWidget *w, int type)
diff --git a/src/designer/src/components/formeditor/formwindow.h b/src/designer/src/components/formeditor/formwindow.h
index 405a631b4..707c7d8a2 100644
--- a/src/designer/src/components/formeditor/formwindow.h
+++ b/src/designer/src/components/formeditor/formwindow.h
@@ -124,8 +124,8 @@ public:
     virtual void setFileName(const QString &fileName);
 
     virtual QString contents() const;
-    virtual void setContents(const QString &contents);
-    virtual void setContents(QIODevice *dev);
+    virtual bool setContents(QIODevice *dev, QString *errorMessage = 0);
+    virtual bool setContents(const QString &);
 
     virtual QDir absoluteDir() const;
 
diff --git a/src/designer/src/components/formeditor/qdesigner_resource.cpp b/src/designer/src/components/formeditor/qdesigner_resource.cpp
index 1627d4275..62957d30b 100644
--- a/src/designer/src/components/formeditor/qdesigner_resource.cpp
+++ b/src/designer/src/components/formeditor/qdesigner_resource.cpp
@@ -411,11 +411,15 @@ DomProperty *QDesignerTextBuilder::saveText(const QVariant &value) const
 QDesignerResource::QDesignerResource(FormWindow *formWindow)  :
     QEditorFormBuilder(formWindow->core()),
     m_formWindow(formWindow),
-    m_topLevelSpacerCount(0),
     m_copyWidget(false),
     m_selected(0),
     m_resourceBuilder(new QDesignerResourceBuilder(m_formWindow->core(), m_formWindow->pixmapCache(), m_formWindow->iconCache()))
 {
+    // Check language unless extension present (Jambi)
+    QDesignerFormEditorInterface *core = m_formWindow->core();
+    if (const QDesignerLanguageExtension *le = qt_extension<QDesignerLanguageExtension*>(core->extensionManager(), core))
+        d->m_language = le->name();
+
     setWorkingDirectory(formWindow->absoluteDir());
     setResourceBuilder(m_resourceBuilder);
     setTextBuilder(new QDesignerTextBuilder());
@@ -451,19 +455,7 @@ static inline QString messageBoxTitle()
 
 void QDesignerResource::save(QIODevice *dev, QWidget *widget)
 {
-    m_topLevelSpacerCount = 0;
-
     QAbstractFormBuilder::save(dev, widget);
-
-    if (QSimpleResource::warningsEnabled() && m_topLevelSpacerCount != 0) {
-        const QString message = QApplication::translate("Designer", "This file contains top level spacers.<br>"
-                           "They have <b>NOT</b> been saved into the form.");
-        const QString infoMessage = QApplication::translate("Designer", "Perhaps you forgot to create a layout?");
-
-        core()->dialogGui()->message(widget->window(), QDesignerDialogGuiInterface::TopLevelSpacerMessage,
-                                     QMessageBox::Warning, messageBoxTitle(), message, infoMessage,
-                                     QMessageBox::Ok);
-    }
 }
 
 void QDesignerResource::saveDom(DomUI *ui, QWidget *widget)
@@ -584,164 +576,10 @@ void QDesignerResource::saveDom(DomUI *ui, QWidget *widget)
     }
 }
 
-namespace {
-    enum LoadPreCheck {  LoadPreCheckFailed, LoadPreCheckVersion3, LoadPreCheckVersionMismatch,  LoadPreCheckOk  };
-    // Pair of major, minor
-    typedef QPair<int, int> UiVersion;
-}
-
-static UiVersion uiVersion(const QString &attr)
-{
-    const QStringList versions = attr.split(QLatin1Char('.'));
-    if (versions.empty())
-        return UiVersion(-1, -1);
-
-    bool ok = false;
-    UiVersion rc(versions.at(0).toInt(&ok), 0);
-
-    if (!ok)
-        return UiVersion(-1, -1);
-
-    if (versions.size() > 1) {
-        const int minorVersion = versions.at(1).toInt(&ok);
-        if (ok)
-            rc.second =  minorVersion;
-    }
-    return rc;
-}
-
-// Read version and language attributes of an <UI> element.
-static bool readUiAttributes(QIODevice *dev, QString *errorMessage,
-                             QString *version,
-                             QString *language)
-{
-    const QString uiElement = QLatin1String("ui");
-    const QString versionAttribute = QLatin1String("version");
-    const QString languageAttribute = QLatin1String("language");
-    QXmlStreamReader reader(dev);
-    // Read up to first element
-    while (!reader.atEnd()) {
-        if (reader.readNext() == QXmlStreamReader::StartElement) {
-            const QStringRef tag = reader.name();
-            if (reader.name().compare(uiElement, Qt::CaseInsensitive) == 0) {
-                const QXmlStreamAttributes attributes = reader.attributes();
-                if (attributes.hasAttribute(versionAttribute))
-                    *version = attributes.value(versionAttribute).toString();
-                if (attributes.hasAttribute(languageAttribute))
-                    *language = attributes.value(languageAttribute).toString();
-                return true;
-            } else {
-                *errorMessage = QCoreApplication::translate("Designer", "Invalid UI file: The root element <ui> is missing.");
-                return false;
-
-            }
-        }
-    }
-    *errorMessage = QCoreApplication::translate("Designer", "An error has occurred while reading the UI file at line %1, column %2: %3")
-                    .arg(reader.lineNumber()).arg(reader.columnNumber()).arg(reader.errorString());
-    return false;
-}
-
-// While loading a file, check language, version and extra extension
-static LoadPreCheck loadPrecheck(QDesignerFormEditorInterface *core,
-                                 QIODevice *dev,
-                                 QString *errorMessage, QString *versionString)
-{
-    QString language;
-    // Read attributes of <ui> and rewind
-    if (!readUiAttributes(dev, errorMessage, versionString, &language)) {
-        // XML error: Mimick the behaviour occurring if an XML error is
-        // detected later on, report to warning log and have embedding
-        // application display a dialog.
-        designerWarning(*errorMessage);
-        errorMessage->clear();
-        return LoadPreCheckFailed;
-    }
-    dev->seek(0);
-
-    // Check language unless extension present (Jambi)
-    if (!language.isEmpty() && !qt_extension<QDesignerLanguageExtension*>(core->extensionManager(), core)) {
-        if (language.toLower() != QLatin1String("c++")) {
-            // Jambi?!
-            *errorMessage = QApplication::translate("Designer", "This file cannot be read because it was created using %1.").arg(language);
-            return LoadPreCheckFailed;
-        }
-    }
-
-    // Version
-    if (!versionString->isEmpty()) {
-        const UiVersion version = uiVersion(*versionString);
-        switch (version.first) {
-        case 3:
-            return  LoadPreCheckVersion3;
-        case 4:
-            break;
-        default:
-            *errorMessage = QApplication::translate("Designer", "This file was created using Designer from Qt-%1 and cannot be read.").arg(*versionString);
-            return LoadPreCheckVersionMismatch;
-        }
-    }
-    return LoadPreCheckOk;
-}
-
 QWidget *QDesignerResource::load(QIODevice *dev, QWidget *parentWidget)
 {
-    // Run loadPreCheck for version and language
-    QString errorMessage;
-    QString version;
-    switch (loadPrecheck(core(), dev,  &errorMessage, &version)) {
-    case LoadPreCheckFailed:
-    case LoadPreCheckVersionMismatch:
-        if (!errorMessage.isEmpty())
-            core()->dialogGui()->message(parentWidget->window(), QDesignerDialogGuiInterface::FormLoadFailureMessage,
-                                         QMessageBox::Warning, messageBoxTitle(), errorMessage, QMessageBox::Ok);
-        return 0;
-    case LoadPreCheckVersion3: {
-        QWidget *w = 0;
-        QByteArray ba;
-        if (runUIC( m_formWindow->fileName(), UIC_ConvertV3, ba, errorMessage)) {
-            QBuffer buffer(&ba);
-            buffer.open(QIODevice::ReadOnly);
-            w = load(&buffer, parentWidget);
-            if (w) {
-                // Force the form to pop up a save file dialog
-                m_formWindow->setFileName(QString());
-            } else {
-                errorMessage = QApplication::translate("Designer", "The converted file could not be read.");
-            }
-        }
-        if (w) {
-            const QString message = QApplication::translate("Designer",
-                                     "This file was created using Designer from Qt-%1 and"
-                                     " will be converted to a new form by Qt Designer.").arg(version);
-            const QString infoMessage = QApplication::translate("Designer",
-                                     "The old form has not been touched, but you will have to save the form"
-                                     " under a new name.");
-
-            core()->dialogGui()->message(parentWidget->window(),
-                                         QDesignerDialogGuiInterface::UiVersionMismatchMessage,
-                                         QMessageBox::Information, messageBoxTitle(), message, infoMessage,
-                                         QMessageBox::Ok);
-            return w;
-        }
-
-        const QString message = QApplication::translate("Designer",
-                             "This file was created using Designer from Qt-%1 and "
-                             "could not be read:\n%2").arg(version).arg(errorMessage);
-        const QString infoMessage = QApplication::translate("Designer",
-                             "Please run it through <b>uic3&nbsp;-convert</b> to convert "
-                             "it to Qt-4's ui format.");
-        core()->dialogGui()->message(parentWidget->window(), QDesignerDialogGuiInterface::FormLoadFailureMessage,
-                                     QMessageBox::Warning, messageBoxTitle(), message, infoMessage,
-                                     QMessageBox::Ok);
-        return 0;
-    }
-
-    case LoadPreCheckOk:
-        break;
-    }
     QWidget *w = QEditorFormBuilder::load(dev, parentWidget);
-    if (w) // Store the class name as 'reset' value for the main container's object name.
+    if (w)  // Store the class name as 'reset' value for the main container's object name.
         w->setProperty("_q_classname", w->objectName());
     return w;
 }
@@ -1005,7 +843,6 @@ QLayoutItem *QDesignerResource::create(DomLayoutItem *ui_layoutItem, QLayout *la
 {
     if (ui_layoutItem->kind() == DomLayoutItem::Spacer) {
         const DomSpacer *domSpacer = ui_layoutItem->elementSpacer();
-        const QHash<QString, DomProperty*> properties = propertyMap(domSpacer->elementProperty());
         Spacer *spacer = static_cast<Spacer*>(core()->widgetFactory()->createWidget(QLatin1String("Spacer"), parentWidget));
         if (domSpacer->hasAttributeName())
             changeObjectName(spacer, domSpacer->attributeName());
@@ -1239,10 +1076,8 @@ DomWidget *QDesignerResource::createDom(QWidget *widget, DomWidget *ui_parentWid
     if (!item)
         return 0;
 
-    if (qobject_cast<Spacer*>(widget) && m_copyWidget == false) {
-        ++m_topLevelSpacerCount;
+    if (qobject_cast<Spacer*>(widget) && m_copyWidget == false)
         return 0;
-    }
 
     const QDesignerWidgetDataBaseInterface *wdb = core()->widgetDataBase();
     QDesignerWidgetDataBaseItemInterface *widgetInfo =  0;
@@ -1453,8 +1288,7 @@ DomWidget *QDesignerResource::saveWidget(QWidget *widget, QDesignerContainerExte
         if (DomWidget *ui_page = createDom(page, ui_widget)) {
             ui_widget_list.append(ui_page);
         } else {
-            if (QSimpleResource::warningsEnabled())
-                designerWarning(msgUnmanagedPage(core(), widget, i, page));
+            designerWarning(msgUnmanagedPage(core(), widget, i, page));
         }
     }
 
@@ -1474,8 +1308,7 @@ DomWidget *QDesignerResource::saveWidget(QStackedWidget *widget, DomWidget *ui_p
             if (DomWidget *ui_page = createDom(page, ui_widget)) {
                 ui_widget_list.append(ui_page);
             } else {
-                if (QSimpleResource::warningsEnabled())
-                    designerWarning(msgUnmanagedPage(core(), widget, i, page));
+                designerWarning(msgUnmanagedPage(core(), widget, i, page));
             }
         }
     }
@@ -1572,8 +1405,7 @@ DomWidget *QDesignerResource::saveWidget(QTabWidget *widget, DomWidget *ui_paren
 
             DomWidget *ui_page = createDom(page, ui_widget);
             if (!ui_page) {
-                if (QSimpleResource::warningsEnabled())
-                    designerWarning(msgUnmanagedPage(core(), widget, i, page));
+                designerWarning(msgUnmanagedPage(core(), widget, i, page));
                 continue;
             }
             QList<DomProperty*> ui_attribute_list;
@@ -1640,8 +1472,7 @@ DomWidget *QDesignerResource::saveWidget(QToolBox *widget, DomWidget *ui_parentW
 
             DomWidget *ui_page = createDom(page, ui_widget);
             if (!ui_page) {
-                if (QSimpleResource::warningsEnabled())
-                    designerWarning(msgUnmanagedPage(core(), widget, i, page));
+                designerWarning(msgUnmanagedPage(core(), widget, i, page));
                 continue;
             }
 
diff --git a/src/designer/src/components/formeditor/qdesigner_resource.h b/src/designer/src/components/formeditor/qdesigner_resource.h
index b7113d162..27a125050 100644
--- a/src/designer/src/components/formeditor/qdesigner_resource.h
+++ b/src/designer/src/components/formeditor/qdesigner_resource.h
@@ -89,7 +89,7 @@ public:
     bool saveRelative() const;
     void setSaveRelative(bool relative);
 
-    virtual QWidget *load(QIODevice *dev, QWidget *parentWidget = 0);
+    virtual QWidget *load(QIODevice *dev, QWidget *parentWidget);
 
 protected:
     using QEditorFormBuilder::create;
@@ -165,7 +165,6 @@ private:
     QHash<QString, QString> m_qt_to_internal;
     QStack<QLayout*> m_chain;
     QHash<QDesignerWidgetDataBaseItemInterface*, bool> m_usedCustomWidgets;
-    int m_topLevelSpacerCount;
     bool m_copyWidget;
     QWidget *m_selected;
     class QDesignerResourceBuilder *m_resourceBuilder;
diff --git a/src/designer/src/designer/qdesigner_actions.cpp b/src/designer/src/designer/qdesigner_actions.cpp
index 323205000..6eddeb99c 100644
--- a/src/designer/src/designer/qdesigner_actions.cpp
+++ b/src/designer/src/designer/qdesigner_actions.cpp
@@ -55,7 +55,6 @@
 #include <qdesigner_formbuilder_p.h>
 #include <qdesigner_utils_p.h>
 #include <iconloader_p.h>
-#include <qsimpleresource_p.h>
 #include <previewmanager_p.h>
 #include <codedialog_p.h>
 #include <qdesigner_formwindowmanager_p.h>
@@ -845,7 +844,7 @@ static void removeBackup(const QString &backupFile)
         QFile::remove(backupFile);
 }
 
-bool QDesignerActions::writeOutForm(QDesignerFormWindowInterface *fw, const QString &saveFile)
+bool QDesignerActions::writeOutForm(QDesignerFormWindowInterface *fw, const QString &saveFile, bool check)
 {
     Q_ASSERT(fw && !saveFile.isEmpty());
 
@@ -854,6 +853,12 @@ bool QDesignerActions::writeOutForm(QDesignerFormWindowInterface *fw, const QStr
     if (fi.exists())
         backupFile = createBackup(saveFile);
 
+    if (check) {
+        const QStringList problems = fw->checkContents();
+        if (!problems.isEmpty())
+            QMessageBox::information(fw->window(), tr("Qt Designer"), problems.join(QLatin1String("<br>")));
+    }
+
     QString contents = fw->contents();
     if (qdesigner_internal::FormWindowBase *fwb = qobject_cast<qdesigner_internal::FormWindowBase *>(fw)) {
         if (fwb->lineTerminatorMode() == qdesigner_internal::FormWindowBase::CRLFLineTerminator)
@@ -1121,7 +1126,6 @@ void QDesignerActions::backupForms()
     QStringList tmpFiles;
     QMap<QString, QString> backupMap;
     QDir backupDir(m_backupPath);
-    const bool warningsEnabled = qdesigner_internal::QSimpleResource::setWarningsEnabled(false);
     for (int i = 0; i < count; ++i) {
         QDesignerFormWindow *fw = m_workbench->formWindow(i);
         QDesignerFormWindowInterface *fwi = fw->editor();
@@ -1153,7 +1157,6 @@ void QDesignerActions::backupForms()
             file.close();
         }
     }
-    qdesigner_internal::QSimpleResource::setWarningsEnabled(warningsEnabled);
     if(!tmpFiles.isEmpty()) {
         const QStringList backupFiles = backupDir.entryList(QDir::Files);
         if(!backupFiles.isEmpty()) {
diff --git a/src/designer/src/designer/qdesigner_actions.h b/src/designer/src/designer/qdesigner_actions.h
index 910901bcb..4bd4de95e 100644
--- a/src/designer/src/designer/qdesigner_actions.h
+++ b/src/designer/src/designer/qdesigner_actions.h
@@ -83,7 +83,7 @@ public:
 
     bool saveForm(QDesignerFormWindowInterface *fw);
     bool readInForm(const QString &fileName);
-    bool writeOutForm(QDesignerFormWindowInterface *formWindow, const QString &fileName);
+    bool writeOutForm(QDesignerFormWindowInterface *formWindow, const QString &fileName, bool check = true);
 
     QActionGroup *fileActions() const;
     QActionGroup *recentFilesActions() const;
diff --git a/src/designer/src/designer/qdesigner_workbench.cpp b/src/designer/src/designer/qdesigner_workbench.cpp
index d6c925dc6..0d646060a 100644
--- a/src/designer/src/designer/qdesigner_workbench.cpp
+++ b/src/designer/src/designer/qdesigner_workbench.cpp
@@ -894,7 +894,6 @@ void QDesignerWorkbench::resizeForm(QDesignerFormWindow *fw, const QWidget *main
 
 QDesignerFormWindow * QDesignerWorkbench::loadForm(const QString &fileName,
                                                    bool detectLineTermiantorMode,
-                                                   bool *uic3Converted,
                                                    QString *errorMessage)
 {
     QFile file(fileName);
@@ -916,11 +915,10 @@ QDesignerFormWindow * QDesignerWorkbench::loadForm(const QString &fileName,
     }
 
     if (!file.open(QFile::ReadOnly|QFile::Text)) {
-        *errorMessage = tr("The file <b>%1</b> could not be opened.").arg(file.fileName());
+        *errorMessage = tr("The file <b>%1</b> could not be opened: %1").arg(file.fileName(), file.errorString());
         return 0;
     }
 
-
     // Create a form
     QDesignerFormWindowManagerInterface *formWindowManager = m_core->formWindowManager();
 
@@ -932,7 +930,13 @@ QDesignerFormWindow * QDesignerWorkbench::loadForm(const QString &fileName,
     // Temporarily set the file name. It is needed when converting a UIC 3 file.
     // In this case, the file name will we be cleared on return to force a save box.
     editor->setFileName(fileName);
-    editor->setContents(&file);
+
+    if (!editor->setContents(&file, errorMessage)) {
+        removeFormWindow(formWindow);
+        formWindowManager->removeFormWindow(editor);
+        m_core->metaDataBase()->remove(editor);
+        return 0;
+    }
 
     if (qdesigner_internal::FormWindowBase *fwb = qobject_cast<qdesigner_internal::FormWindowBase *>(editor))
         fwb->setLineTerminatorMode(mode);
@@ -958,14 +962,6 @@ QDesignerFormWindow * QDesignerWorkbench::loadForm(const QString &fileName,
         break;
     }
 
-    if (!editor->mainContainer()) {
-        removeFormWindow(formWindow);
-        formWindowManager->removeFormWindow(editor);
-        m_core->metaDataBase()->remove(editor);
-        *errorMessage = tr("The file <b>%1</b> is not a valid Designer UI file.").arg(file.fileName());
-        return 0;
-    }
-    *uic3Converted = editor->fileName().isEmpty();
     // Did user specify another (missing) resource path -> set dirty.
     const bool dirty = editor->property("_q_resourcepathchanged").toBool();
     editor->setDirty(dirty);
@@ -977,13 +973,10 @@ QDesignerFormWindow * QDesignerWorkbench::loadForm(const QString &fileName,
 
 QDesignerFormWindow * QDesignerWorkbench::openForm(const QString &fileName, QString *errorMessage)
 {
-    bool uic3Converted;
-    QDesignerFormWindow *rc =loadForm(fileName, true, &uic3Converted, errorMessage);
+    QDesignerFormWindow *rc = loadForm(fileName, true, errorMessage);
     if (!rc)
         return 0;
-
-    if (!uic3Converted)
-        rc->editor()->setFileName(fileName);
+    rc->editor()->setFileName(fileName);
     rc->firstShow();
     return rc;
 }
@@ -992,14 +985,11 @@ QDesignerFormWindow * QDesignerWorkbench::openTemplate(const QString &templateFi
                                                        const QString &editorFileName,
                                                        QString *errorMessage)
 {
-    bool uic3Converted;
-    QDesignerFormWindow *rc =loadForm(templateFileName, false, &uic3Converted, errorMessage);
+    QDesignerFormWindow *rc = loadForm(templateFileName, false, errorMessage);
     if (!rc)
         return 0;
 
-    if (!uic3Converted)
-        rc->editor()->setFileName(editorFileName);
-
+    rc->editor()->setFileName(editorFileName);
     rc->firstShow();
     return rc;
 }
diff --git a/src/designer/src/designer/qdesigner_workbench.h b/src/designer/src/designer/qdesigner_workbench.h
index d174baaa6..edbb12aa6 100644
--- a/src/designer/src/designer/qdesigner_workbench.h
+++ b/src/designer/src/designer/qdesigner_workbench.h
@@ -148,7 +148,7 @@ private:
     QDesignerFormWindowManagerInterface *formWindowManager() const;
     void closeAllToolWindows();
     QDesignerToolWindow *widgetBoxToolWindow() const;
-    QDesignerFormWindow *loadForm(const QString &fileName, bool detectLineTermiantorMode, bool *uic3Converted, QString *errorMessage);
+    QDesignerFormWindow *loadForm(const QString &fileName, bool detectLineTermiantorMode, QString *errorMessage);
     void resizeForm(QDesignerFormWindow *fw,  const QWidget *mainContainer) const;
     void saveGeometriesForModeChange();
     void saveGeometries(QDesignerSettings &settings) const;
diff --git a/src/designer/src/lib/sdk/abstractformwindow.cpp b/src/designer/src/lib/sdk/abstractformwindow.cpp
index 8e37b9f78..bba78bf45 100644
--- a/src/designer/src/lib/sdk/abstractformwindow.cpp
+++ b/src/designer/src/lib/sdk/abstractformwindow.cpp
@@ -328,9 +328,21 @@ void QDesignerFormWindowInterface::activateResourceFilePaths(const QStringList &
 */
 
 /*!
-    \fn virtual void QDesignerFormWindowInterface::setContents(QIODevice *device)
+    \fn virtual QStringList QDesignerFormWindowInterface::checkContents() const
 
-    Sets the form's contents using data obtained from the given \a device.
+    Performs checks on the current form and returns a list of richtext warnings
+    about potential issues (for example, top level spacers on unlaid-out forms).
+
+    IDE integrations can call this before handling starting a save operation.
+
+    \since 5.0
+*/
+
+/*!
+    \fn virtual bool QDesignerFormWindowInterface::setContents(QIODevice *device, QString *errorMessage = 0)
+
+    Sets the form's contents using data obtained from the given \a device and returns whether
+    loading succeeded. If it fails, the error message is returned in \a errorMessage.
 
     Data can be read from QFile objects or any other subclass of QIODevice.
 */
@@ -742,10 +754,10 @@ void QDesignerFormWindowInterface::activateResourceFilePaths(const QStringList &
 */
 
 /*!
-    \fn virtual void QDesignerFormWindowInterface::setContents(const QString &contents)
+    \fn virtual bool QDesignerFormWindowInterface::setContents(const QString &contents)
 
     Sets the contents of the form using data read from the specified
-    \a contents string.
+    \a contents string and returns whether the operation succeeded.
 
     \sa contents()
 */
diff --git a/src/designer/src/lib/sdk/abstractformwindow.h b/src/designer/src/lib/sdk/abstractformwindow.h
index cf91864e2..ab0f241ce 100644
--- a/src/designer/src/lib/sdk/abstractformwindow.h
+++ b/src/designer/src/lib/sdk/abstractformwindow.h
@@ -85,7 +85,8 @@ public:
     virtual QDir absoluteDir() const = 0;
 
     virtual QString contents() const = 0;
-    virtual void setContents(QIODevice *dev) = 0;
+    virtual QStringList checkContents() const = 0;
+    virtual bool setContents(QIODevice *dev, QString *errorMessage = 0) = 0;
 
     virtual Feature features() const = 0;
     virtual bool hasFeature(Feature f) const = 0;
@@ -168,7 +169,7 @@ public Q_SLOTS:
     virtual void selectWidget(QWidget *w, bool select = true) = 0;
     virtual void setGrid(const QPoint &grid) = 0;
     virtual void setFileName(const QString &fileName) = 0;
-    virtual void setContents(const QString &contents) = 0;
+    virtual bool setContents(const QString &contents) = 0;
 
     virtual void editWidgets() = 0;
     void activateResourceFilePaths(const QStringList &paths, int *errorCount = 0, QString *errorMessages = 0);
diff --git a/src/designer/src/lib/sdk/abstractlanguage.h b/src/designer/src/lib/sdk/abstractlanguage.h
index 37c0c5de0..8026bade5 100644
--- a/src/designer/src/lib/sdk/abstractlanguage.h
+++ b/src/designer/src/lib/sdk/abstractlanguage.h
@@ -70,6 +70,14 @@ class QDesignerLanguageExtension
 public:
     virtual ~QDesignerLanguageExtension() {}
 
+    /*!
+        Returns the name to be matched against the "language" attribute of the <ui> element.
+
+        \since 5.0
+     */
+
+    virtual QString name() const = 0;
+
     virtual QDialog *createFormWindowSettingsDialog(QDesignerFormWindowInterface *formWindow, QWidget *parentWidget) = 0;
     virtual QDesignerResourceBrowserInterface *createResourceBrowser(QWidget *parentWidget) = 0;
 
diff --git a/src/designer/src/lib/shared/codedialog.cpp b/src/designer/src/lib/shared/codedialog.cpp
index 2420aa54a..f6ea29048 100644
--- a/src/designer/src/lib/shared/codedialog.cpp
+++ b/src/designer/src/lib/shared/codedialog.cpp
@@ -188,7 +188,7 @@ bool CodeDialog::generateCode(const QDesignerFormWindowInterface *fw,
     tempFormFile.close();
     // Run uic
     QByteArray rc;
-    if (!runUIC(tempFormFileName, UIC_GenerateCode, rc, *errorMessage))
+    if (!runUIC(tempFormFileName, rc, *errorMessage))
         return false;
     *code = QString::fromUtf8(rc);
     return true;
diff --git a/src/designer/src/lib/shared/formwindowbase.cpp b/src/designer/src/lib/shared/formwindowbase.cpp
index 83bf05796..5875ae953 100644
--- a/src/designer/src/lib/shared/formwindowbase.cpp
+++ b/src/designer/src/lib/shared/formwindowbase.cpp
@@ -50,8 +50,7 @@
 #include "grid_p.h" 
 #include "deviceprofile_p.h"
 #include "qdesigner_utils_p.h"
-
-#include "qsimpleresource_p.h"
+#include "spacer_widget_p.h"
 
 #include <QtDesigner/QDesignerFormEditorInterface>
 #include <QtDesigner/QDesignerContainerExtension>
@@ -487,12 +486,22 @@ void FormWindowBase::triggerDefaultAction(QWidget *widget)
         QTimer::singleShot(0, action, SIGNAL(triggered()));
 }
 
-QString FormWindowBase::fileContents() const
+QStringList FormWindowBase::checkContents() const
 {
-    const bool oldValue = QSimpleResource::setWarningsEnabled(false);
-    const QString rc = contents();
-    QSimpleResource::setWarningsEnabled(oldValue);
-    return rc;
+    if (!mainContainer())
+        return QStringList(tr("Invalid form"));
+    // Test for non-laid toplevel spacers, which will not be saved
+    // as not to throw off uic.
+    QStringList problems;
+    foreach (const Spacer *spacer, mainContainer()->findChildren<Spacer *>()) {
+        if (spacer->parentWidget() && !spacer->parentWidget()->layout()) {
+            problems.push_back(tr("<p>This file contains top level spacers.<br>"
+                                  "They will <b>not</b> be saved.</p><p>"
+                                  "Perhaps you forgot to create a layout?</p>"));
+            break;
+        }
+    }
+    return problems;
 }
 
 } // namespace qdesigner_internal
diff --git a/src/designer/src/lib/shared/formwindowbase_p.h b/src/designer/src/lib/shared/formwindowbase_p.h
index 91f6a306d..9521d068b 100644
--- a/src/designer/src/lib/shared/formwindowbase_p.h
+++ b/src/designer/src/lib/shared/formwindowbase_p.h
@@ -89,8 +89,7 @@ public:
     QVariantMap formData();
     void setFormData(const QVariantMap &vm);
 
-    // Return contents without warnings. Should be 'contents(bool quiet)'
-    QString fileContents() const;
+    virtual QStringList checkContents() const;
 
     // Deprecated
     virtual QPoint grid() const;
diff --git a/src/designer/src/lib/shared/qdesigner_formbuilder.cpp b/src/designer/src/lib/shared/qdesigner_formbuilder.cpp
index 59e32cd7e..a11514734 100644
--- a/src/designer/src/lib/shared/qdesigner_formbuilder.cpp
+++ b/src/designer/src/lib/shared/qdesigner_formbuilder.cpp
@@ -133,14 +133,6 @@ QString QDesignerFormBuilder::systemStyle() const
         m_deviceProfile.style();
 }
 
-QWidget *QDesignerFormBuilder::createWidgetFromContents(const QString &contents, QWidget *parentWidget)
-{
-    QByteArray data = contents.toUtf8();
-    QBuffer buffer(&data);
-    buffer.open(QIODevice::ReadOnly);
-    return load(&buffer, parentWidget);
-}
-
 QWidget *QDesignerFormBuilder::create(DomUI *ui, QWidget *parentWidget)
 {
     m_mainWidget = true;
@@ -383,9 +375,7 @@ QWidget *QDesignerFormBuilder::createPreview(const QDesignerFormWindowInterface
     QDesignerFormBuilder builder(fw->core(), EnableScripts, deviceProfile);
     builder.setWorkingDirectory(fw->absoluteDir());
 
-    const bool warningsEnabled = QSimpleResource::setWarningsEnabled(false);
     QByteArray bytes = fw->contents().toUtf8();
-    QSimpleResource::setWarningsEnabled(warningsEnabled);
 
     QBuffer buffer(&bytes);
     buffer.open(QIODevice::ReadOnly);
diff --git a/src/designer/src/lib/shared/qdesigner_formbuilder_p.h b/src/designer/src/lib/shared/qdesigner_formbuilder_p.h
index 2f902e394..9595d203c 100644
--- a/src/designer/src/lib/shared/qdesigner_formbuilder_p.h
+++ b/src/designer/src/lib/shared/qdesigner_formbuilder_p.h
@@ -90,8 +90,6 @@ public:
                          Mode mode,
                          const DeviceProfile &deviceProfile = DeviceProfile());
 
-    QWidget *createWidgetFromContents(const QString &contents, QWidget *parentWidget = 0);
-
     virtual QWidget *createWidget(DomWidget *ui_widget, QWidget *parentWidget = 0)
     { return QFormBuilder::create(ui_widget, parentWidget); }
 
diff --git a/src/designer/src/lib/shared/qdesigner_utils.cpp b/src/designer/src/lib/shared/qdesigner_utils.cpp
index 5f0a68595..a7c11bd82 100644
--- a/src/designer/src/lib/shared/qdesigner_utils.cpp
+++ b/src/designer/src/lib/shared/qdesigner_utils.cpp
@@ -774,23 +774,11 @@ namespace qdesigner_internal
         return action;
     }
 
-    QDESIGNER_SHARED_EXPORT bool runUIC(const QString &fileName, UIC_Mode mode, QByteArray& ba, QString &errorMessage)
+    QDESIGNER_SHARED_EXPORT bool runUIC(const QString &fileName, QByteArray& ba, QString &errorMessage)
     {
-        QStringList argv;
-        QString binary = QLibraryInfo::location(QLibraryInfo::BinariesPath);
-        binary += QDir::separator();
-        switch (mode) {
-        case UIC_GenerateCode:
-            binary += QLatin1String("uic");
-            break;
-        case UIC_ConvertV3:
-            binary += QLatin1String("uic3");
-            argv += QLatin1String("-convert");
-            break;
-        }
-        argv += fileName;
+        const QString binary = QLibraryInfo::location(QLibraryInfo::BinariesPath) + QLatin1String("/uic");
         QProcess uic;
-        uic.start(binary, argv);
+        uic.start(binary, QStringList(fileName));
         if (!uic.waitForStarted()) {
             errorMessage = QApplication::translate("Designer", "Unable to launch %1.").arg(binary);
             return false;
diff --git a/src/designer/src/lib/shared/qdesigner_utils_p.h b/src/designer/src/lib/shared/qdesigner_utils_p.h
index 1e48cf8db..1c915e036 100644
--- a/src/designer/src/lib/shared/qdesigner_utils_p.h
+++ b/src/designer/src/lib/shared/qdesigner_utils_p.h
@@ -424,8 +424,7 @@ QDESIGNER_SHARED_EXPORT QDesignerFormWindowCommand *createTextPropertyCommand(co
 QDESIGNER_SHARED_EXPORT QAction *preferredEditAction(QDesignerFormEditorInterface *core, QWidget *managedWidget);
 
 // Convenience to run UIC
-enum UIC_Mode { UIC_GenerateCode, UIC_ConvertV3 };
-QDESIGNER_SHARED_EXPORT bool runUIC(const QString &fileName, UIC_Mode mode, QByteArray& ba, QString &errorMessage);
+QDESIGNER_SHARED_EXPORT bool runUIC(const QString &fileName, QByteArray& ba, QString &errorMessage);
 
 // Find a suitable variable name for a class.
 QDESIGNER_SHARED_EXPORT QString qtify(const QString &name);
diff --git a/src/designer/src/lib/shared/qsimpleresource.cpp b/src/designer/src/lib/shared/qsimpleresource.cpp
index 48c74b8f4..cced5954e 100644
--- a/src/designer/src/lib/shared/qsimpleresource.cpp
+++ b/src/designer/src/lib/shared/qsimpleresource.cpp
@@ -216,18 +216,6 @@ QString QSimpleResource::customWidgetScript(QDesignerFormEditorInterface *, cons
     return QString();
 }
 
-bool QSimpleResource::setWarningsEnabled(bool warningsEnabled)
-{
-    const bool rc = m_warningsEnabled;
-    m_warningsEnabled = warningsEnabled;
-    return rc;
-}
-
-bool QSimpleResource::warningsEnabled()
-{
-    return m_warningsEnabled;
-}
-
 // Custom widgets handling helpers
 
 // Add unique fake slots and signals to lists
diff --git a/src/designer/src/lib/shared/qsimpleresource_p.h b/src/designer/src/lib/shared/qsimpleresource_p.h
index b4f85bd0c..e8f4f3f95 100644
--- a/src/designer/src/lib/shared/qsimpleresource_p.h
+++ b/src/designer/src/lib/shared/qsimpleresource_p.h
@@ -90,9 +90,6 @@ public:
                                           QDesignerFormEditorInterface *core,
                                           DomWidget *ui_widget, QWidget *widget,
                                           bool applyState);
-    // Enable warnings while saving. Turn off for backups.
-    static bool setWarningsEnabled(bool warningsEnabled);
-    static bool warningsEnabled();
     // Return the script returned by the CustomWidget codeTemplate API
     static QString customWidgetScript(QDesignerFormEditorInterface *core, QObject *object);
     static QString customWidgetScript(QDesignerFormEditorInterface *core, const QString &className);