Add AsyncTask helper functions

src/CMakeLists.txt

@@ -38,6 +38,7 @@ configure_file(version.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/version.h @ONLY)
 
 set(keepassx_SOURCES
     core/AutoTypeAssociations.cpp
+    core/AsyncTask.h
     core/Config.cpp
     core/CsvParser.cpp
     core/Database.cpp

src/core/AsyncTask.h

@@ -0,0 +1,63 @@
+/*
+ *  Copyright (C) 2017 KeePassXC Team <team@keepassxc.org>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef KEEPASSXC_ASYNCTASK_HPP
+#define KEEPASSXC_ASYNCTASK_HPP
+
+#include <QFuture>
+#include <QFutureWatcher>
+#include <QtConcurrent>
+
+
+/**
+ * Asynchronously run computations outside the GUI thread.
+ */
+namespace AsyncTask
+{
+
+/**
+ * Wait for the given future without blocking the event loop.
+ *
+ * @param future future to wait for
+ * @return async task result
+ */
+template<typename FunctionObject>
+typename std::result_of<FunctionObject()>::type waitForFuture(QFuture<typename std::result_of<FunctionObject()>::type> future)
+{
+    QEventLoop loop;
+    QFutureWatcher<typename std::result_of<FunctionObject()>::type> watcher;
+    QObject::connect(&watcher, SIGNAL(finished()), &loop, SLOT(quit()));
+    watcher.setFuture(future);
+    loop.exec();
+    return future.result();
+}
+
+/**
+ * Run a given task and wait for it to finish without blocking the event loop.
+ *
+ * @param task std::function object to run
+ * @return async task result
+ */
+template<typename FunctionObject>
+typename std::result_of<FunctionObject()>::type runAndWaitForFuture(FunctionObject task)
+{
+    return waitForFuture<FunctionObject>(QtConcurrent::run(task));
+}
+
+};  // namespace AsyncTask
+
+#endif //KEEPASSXC_ASYNCTASK_HPP

src/gui/DatabaseSettingsWidget.cpp

@@ -18,28 +18,18 @@
 #include "DatabaseSettingsWidget.h"
 #include "ui_DatabaseSettingsWidget.h"
 
-#include <QList>
-#include <QLabel>
-#include <QPushButton>
-#include <QHBoxLayout>
-#include <QSpinBox>
 #include <QMessageBox>
-#include <QDialogButtonBox>
 
+#include "core/AsyncTask.h"
 #include "core/Database.h"
 #include "core/Group.h"
 #include "core/Metadata.h"
 #include "crypto/SymmetricCipher.h"
-#include "format/KeePass2.h"
-#include "keys/CompositeKey.h"
-#include "format/KeePass2.h"
-#include "crypto/kdf/Kdf.h"
 #include "MessageBox.h"
 
 DatabaseSettingsWidget::DatabaseSettingsWidget(QWidget* parent)
     : DialogyWidget(parent)
     , m_ui(new Ui::DatabaseSettingsWidget())
-    , m_benchmarkField(nullptr)
     , m_db(nullptr)
 {
     m_ui->setupUi(this);
@@ -51,6 +41,7 @@ DatabaseSettingsWidget::DatabaseSettingsWidget(QWidget* parent)
     connect(m_ui->historyMaxSizeCheckBox, SIGNAL(toggled(bool)),
             m_ui->historyMaxSizeSpinBox, SLOT(setEnabled(bool)));
     connect(m_ui->kdfComboBox, SIGNAL(currentIndexChanged(int)), SLOT(changeKdf(int)));
+    connect(m_ui->transformBenchmarkButton, SIGNAL(clicked()), SLOT(transformRoundsBenchmark()));
 }
 
 DatabaseSettingsWidget::~DatabaseSettingsWidget()
@@ -111,6 +102,7 @@ void DatabaseSettingsWidget::load(Database* db)
     }
     displayKdf(*m_kdf);
     m_ui->kdfComboBox->blockSignals(blockSignals);
+    m_ui->transformRoundsSpinBox->setValue(static_cast<unsigned>(m_kdf->rounds()));
 
     m_ui->dbNameEdit->setFocus();
 }
@@ -191,13 +183,12 @@ void DatabaseSettingsWidget::reject()
 
 void DatabaseSettingsWidget::transformRoundsBenchmark()
 {
-    if (m_benchmarkField == nullptr) {
-        Q_ASSERT(false);
-        return;
-    }
     QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
-    m_benchmarkField->setValue(m_kdf->benchmark(1000));
+    m_ui->transformRoundsSpinBox->setValue(AsyncTask::runAndWaitForFuture([this]() {
+        int rounds = m_kdf->benchmark(1000);
         QApplication::restoreOverrideCursor();
+        return rounds;
+    }));
 }
 
 void DatabaseSettingsWidget::truncateHistories()

src/gui/DatabaseSettingsWidget.h

@@ -28,7 +28,8 @@
 
 class Database;
 
-namespace Ui {
+namespace Ui
+{
 class DatabaseSettingsWidget;
 }
 
@@ -58,8 +59,6 @@ private:
 
     const QScopedPointer<Ui::DatabaseSettingsWidget> m_ui;
     QList<QWidget*> m_kdfWidgets;
-    QList<QPair<quint32, QSpinBox*>> m_kdfFields;
-    QSpinBox* m_benchmarkField;
     QScopedPointer<Kdf> m_kdf;
     Database* m_db;