Don't show msgboxes outside of the GUI thread

Fixes #511

src/core.cpp

@@ -1106,7 +1106,7 @@ bool Core::loadConfiguration(QString path)
         {
             emit blockingGetPassword(tr("Tox datafile decryption password"), ptMain);
             if (!isPasswordSet(ptMain))
-                QMessageBox::warning(nullptr, tr("Password error"), tr("Failed to setup password.\nEmpty password."));
+                Widget::getInstance()->showWarningMsgBox(tr("Password error"), tr("Failed to setup password.\nEmpty password."));
         }
     }
 
@@ -1126,7 +1126,7 @@ bool Core::loadConfiguration(QString path)
                 {
                     emit blockingGetPassword(tr("Tox datafile decryption password"), ptMain);
                     if (!isPasswordSet(ptMain))
-                        QMessageBox::warning(nullptr, tr("Password error"), tr("Failed to setup password.\nEmpty password."));
+                        Widget::getInstance()->showWarningMsgBox(tr("Password error"), tr("Failed to setup password.\nEmpty password."));
                 }
 
                 error = tox_encrypted_load(tox, reinterpret_cast<uint8_t *>(data.data()), data.size(),
@@ -1134,6 +1134,7 @@ bool Core::loadConfiguration(QString path)
                 if (error != 0)
                 {
                     QMessageBox msgb;
+                    msgb.moveToThread(qApp->thread());
                     QPushButton *tryAgain = msgb.addButton(tr("Try Again"), QMessageBox::AcceptRole);
                     QPushButton *cancel = msgb.addButton(tr("Change profile"), QMessageBox::RejectRole);
                     QPushButton *wipe = msgb.addButton(tr("Reinit current profile"), QMessageBox::ActionRole);
@@ -1174,12 +1175,12 @@ bool Core::loadConfiguration(QString path)
             {
                 emit blockingGetPassword(tr("History Log decpytion password"), Core::ptHistory);
                 if (!isPasswordSet(ptHistory))
-                    QMessageBox::warning(nullptr, tr("Password error"), tr("Failed to setup password.\nEmpty password."));
+                    Widget::getInstance()->showWarningMsgBox(tr("Password error"), tr("Failed to setup password.\nEmpty password."));
             }
 
             if (!HistoryKeeper::checkPassword())
             {
-                if (QMessageBox::Ok == QMessageBox::warning(nullptr, tr("Encrypted log"),
+                if (QMessageBox::Ok == Widget::getInstance()->showWarningMsgBox(tr("Encrypted log"),
                                                             tr("Your history encrypted with different password\nDo you want to try another password?"),
                                                             QMessageBox::Ok | QMessageBox::Cancel))
                 {
@@ -1188,7 +1189,7 @@ bool Core::loadConfiguration(QString path)
                 } else {
                     error = false;
                     clearPassword(ptHistory);
-                    QMessageBox::warning(nullptr, tr("Loggin"), tr("Due to incorret password logging will be disabled"));
+                    Widget::getInstance()->showWarningMsgBox(tr("Loggin"), tr("Due to incorret password logging will be disabled"));
                     Settings::getInstance().setEncryptLogs(false);
                     Settings::getInstance().setEnableLogging(false);
                 }
@@ -1275,7 +1276,7 @@ void Core::saveConfiguration(const QString& path)
             if (!isPasswordSet(ptMain))
             {
                 // probably zero chance event
-                QMessageBox::warning(nullptr, tr("NO Password"), tr("Will be saved without encryption!"));
+                Widget::getInstance()->showWarningMsgBox(tr("NO Password"), tr("Will be saved without encryption!"));
                 tox_save(tox, data);
             } else {
                 int ret = tox_encrypted_save(tox, data, reinterpret_cast<uint8_t *>(barePassword[ptMain].data()),

src/widget/widget.cpp

@@ -1040,3 +1040,21 @@ void Widget::getPassword(QString info, int passtype)
             core->setPassword(pswd, pt);
     }
 }
+
+QMessageBox::StandardButton Widget::showWarningMsgBox(const QString& title, const QString& msg, QMessageBox::StandardButtons buttons)
+{
+    // We can only display widgets from the GUI thread
+    if (QThread::currentThread() != qApp->thread())
+    {
+        QMessageBox::StandardButton ret;
+        QMetaObject::invokeMethod(this, "showWarningMsgBox", Qt::BlockingQueuedConnection,
+                                  Q_RETURN_ARG(QMessageBox::StandardButton, ret),
+                                  Q_ARG(const QString&, title), Q_ARG(const QString&, msg),
+                                  Q_ARG(QMessageBox::StandardButtons, buttons));
+        return ret;
+    }
+    else
+    {
+        return QMessageBox::warning(this, title, msg, buttons);
+    }
+}

src/widget/widget.h

@@ -19,6 +19,7 @@
 
 #include <QMainWindow>
 #include <QSystemTrayIcon>
+#include <QMessageBox>
 #include "form/addfriendform.h"
 #include "form/settingswidget.h"
 #include "form/settings/identityform.h"
@@ -63,6 +64,8 @@ public:
     void clearContactsList();
     void setIdleTimer(int minutes);
     void setTranslation();
+    Q_INVOKABLE QMessageBox::StandardButton showWarningMsgBox(const QString& title, const QString& msg,
+                                              QMessageBox::StandardButtons buttonss = QMessageBox::Ok);
     ~Widget();
 
     virtual void closeEvent(QCloseEvent *event);