TextEditor: Disable Search & Replace buttons when folder doesn't exist

In case of searching in scope: "Files on File System" when specified
directory does not exist, "Search" and "Search & Replace" buttons
should be disabled.

Task-number: QTCREATORBUG-5959
Change-Id: I1905cbea08aa07d72b96e9ad893ef3928d633c4f
Reviewed-by: Robert Loehning <robert.loehning@theqtcompany.com>

src/plugins/coreplugin/find/findtoolwindow.cpp

@@ -92,7 +92,8 @@ bool FindToolWindow::event(QEvent *event)
         if ((ke->key() == Qt::Key_Return || ke->key() == Qt::Key_Enter)
                 && (ke->modifiers() == Qt::NoModifier || ke->modifiers() == Qt::KeypadModifier)) {
             ke->accept();
-            search();
+            if (m_ui.searchButton->isEnabled())
+                search();
             return true;
         }
     }
@@ -115,7 +116,7 @@ bool FindToolWindow::eventFilter(QObject *obj, QEvent *event)
 void FindToolWindow::updateButtonStates()
 {
     bool filterEnabled = m_currentFilter && m_currentFilter->isEnabled();
-    bool enabled = !m_ui.searchTerm->text().isEmpty() && filterEnabled;
+    bool enabled = !m_ui.searchTerm->text().isEmpty() && filterEnabled && m_currentFilter->isValid();
     m_ui.searchButton->setEnabled(enabled);
     m_ui.replaceButton->setEnabled(m_currentFilter
                                    && m_currentFilter->isReplaceSupported() && enabled);

src/plugins/coreplugin/find/ifindfilter.h

@@ -48,6 +48,7 @@ public:
     virtual QString displayName() const = 0;
     ///
     virtual bool isEnabled() const = 0;
+    virtual bool isValid() const { return true; }
     virtual QKeySequence defaultShortcut() const;
     virtual bool isReplaceSupported() const { return false; }
     virtual FindFlags supportedFindFlags() const;

src/plugins/texteditor/findinfiles.cpp

@@ -62,6 +62,11 @@ FindInFiles::~FindInFiles()
 {
 }
 
+bool FindInFiles::isValid() const
+{
+    return m_directory->isValid();
+}
+
 QString FindInFiles::id() const
 {
     return QLatin1String("Files on Disk");

src/plugins/texteditor/findinfiles.h

@@ -52,6 +52,7 @@ public:
     QWidget *createConfigWidget();
     void writeSettings(QSettings *settings);
     void readSettings(QSettings *settings);
+    bool isValid() const;
 
     void setDirectory(const Utils::FileName &directory);
     static void findOnFileSystem(const QString &path);