ClangFormat: Add export and import features for ClangFormat

Due to the removal of the widget where users could generate settings
using BasedOnStyle and see all available properties, users now need
to have the ability to load their files or generated files.

- Implemented functionality to export internal .clang-format to an
  external file
- Added import capability to load ClangFormat style from an external
  file
- Added to the ICodeStylePreferencesFactory function
  createSelectorWidget for the possibility of reimplementing the
  functionality of export and import buttons

Change-Id: Ib5f00a0fb58a983d0e7c6dc55128e93d0205d3ca
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/clangformat/clangformatglobalconfigwidget.cpp

@@ -5,6 +5,7 @@
 
 #include "clangformatconfigwidget.h"
 #include "clangformatconstants.h"
+#include "clangformatfile.h"
 #include "clangformatindenter.h"
 #include "clangformatsettings.h"
 #include "clangformattr.h"
@@ -17,6 +18,8 @@
 #include <projectexplorer/project.h>
 #include <projectexplorer/projecttree.h>
 
+#include <texteditor/codestylepool.h>
+#include <texteditor/codestyleselectorwidget.h>
 #include <texteditor/icodestylepreferences.h>
 #include <texteditor/texteditorsettings.h>
 
@@ -27,7 +30,9 @@
 #include <QCheckBox>
 #include <QComboBox>
 #include <QGroupBox>
+#include <QInputDialog>
 #include <QLabel>
+#include <QMessageBox>
 #include <QSpinBox>
 
 using namespace CppEditor;
@@ -350,6 +355,59 @@ void ClangFormatGlobalConfigWidget::finish()
         !ClangFormatSettings::instance().useCustomSettings());
 }
 
+class ClangFormatSelectorWidget final : public CodeStyleSelectorWidget
+{
+public:
+    ClangFormatSelectorWidget(
+        ICodeStylePreferencesFactory *factory,
+        ProjectExplorer::Project *project = nullptr,
+        QWidget *parent = nullptr)
+        : CodeStyleSelectorWidget(factory, project, parent)
+    {}
+
+private:
+    void slotImportClicked() final
+    {
+        const FilePath filePath =
+            FileUtils::getOpenFilePath(this, Tr::tr("Import Code Format"), {},
+                                       Tr::tr("Clang Format (*clang-format*);;All files (*)"));
+        if (!filePath.isEmpty()) {
+            QString name = QInputDialog::getText(
+                this,
+                Tr::tr("Import Code Style"),
+                Tr::tr("Enter a name for the imported code style:"));
+            if (name.isEmpty())
+                return;
+
+            CodeStylePool *codeStylePool = m_codeStyle->delegatingPool();
+            ICodeStylePreferences *importedStyle = codeStylePool->createCodeStyle(name);
+            ClangFormatFile file(importedStyle, filePath);
+
+            if (importedStyle)
+                m_codeStyle->setCurrentDelegate(importedStyle);
+            else
+                QMessageBox::warning(this,
+                                     Tr::tr("Import Code Style"),
+                                     Tr::tr("Cannot import code style from \"%1\".")
+                                         .arg(filePath.toUserOutput()));
+        }
+    }
+
+    void slotExportClicked() final
+    {
+        ICodeStylePreferences *currentPreferences = m_codeStyle->currentPreferences();
+        const FilePath filePath = FileUtils::getSaveFilePath(
+            this,
+            Tr::tr("Export Code Format"),
+            FileUtils::homePath(),
+            Tr::tr("Clang Format (*clang-format*);;All files (*)"));
+        if (!filePath.isEmpty()) {
+            FilePath clangFormatFile = filePathToCurrentSettings(currentPreferences);
+            clangFormatFile.copyFile(filePath);
+        }
+    }
+};
+
 class ClangFormatStyleFactory final : public CppCodeStylePreferencesFactory
 {
 public:
@@ -369,6 +427,12 @@ public:
     {
         return new ClangFormatGlobalConfigWidget(codeStyle, project, parent);
     }
+
+    CodeStyleSelectorWidget *createSelectorWidget(
+        ProjectExplorer::Project *project, QWidget *parent) final
+    {
+        return new ClangFormatSelectorWidget(this, project, parent);
+    }
 };
 
 void setupClangFormatStyleFactory(QObject *guard)