Show current database action in status bar and add cancel button

This adds a label to the status bar which becomes visible whenever the
database is busy. It also specifies the currently running action. Also
add a button which allows you to cancel this action at the next
opportunity.

Note that this doesn't work for the Execute SQL tab yet which requires
some more rewriting of the code there.

src/MainWindow.cpp

@@ -311,6 +311,20 @@ void MainWindow::init()
 #endif
 
     // Set statusbar fields
+    statusBusyLabel = new QLabel(ui->statusbar);
+    statusBusyLabel->setEnabled(false);
+    statusBusyLabel->setVisible(false);
+    statusBusyLabel->setToolTip(tr("The database is currenctly busy."));
+    ui->statusbar->addPermanentWidget(statusBusyLabel);
+
+    statusStopButton = new QToolButton(ui->statusbar);
+    statusStopButton->setVisible(false);
+    statusStopButton->setIcon(QIcon(":icons/cancel"));
+    statusStopButton->setToolTip(tr("Click here to interrupt the currently running query."));
+    statusStopButton->setMaximumSize(ui->statusbar->geometry().height() - 6, ui->statusbar->geometry().height() - 6);
+    statusStopButton->setAutoRaise(true);
+    ui->statusbar->addPermanentWidget(statusStopButton);
+
     statusEncryptionLabel = new QLabel(ui->statusbar);
     statusEncryptionLabel->setEnabled(false);
     statusEncryptionLabel->setVisible(false);
@@ -341,6 +355,11 @@ void MainWindow::init()
         ui->editDeleteObjectAction->setToolTip(ui->editDeleteObjectAction->text());
     });
 
+    // When clicking the interrupt query button in the status bar, ask SQLite to interrupt the current query
+    connect(statusStopButton, &QToolButton::clicked, [this]() {
+       db.interruptQuery();
+    });
+
     // Connect some more signals and slots
     connect(ui->dataTable->filterHeader(), SIGNAL(sectionClicked(int)), this, SLOT(browseTableHeaderClicked(int)));
     connect(ui->dataTable->verticalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(setRecordsetLabel()));
@@ -357,6 +376,8 @@ void MainWindow::init()
     connect(ui->dataTable, &ExtendedTableWidget::selectedRowsToBeDeleted, this, &MainWindow::deleteRecord);
     connect(ui->actionDropQualifiedCheck, &QAction::toggled, dbStructureModel, &DbStructureModel::setDropQualifiedNames);
     connect(ui->actionEnquoteNamesCheck, &QAction::toggled, dbStructureModel, &DbStructureModel::setDropEnquotedNames);
+    connect(&db, &DBBrowserDB::databaseInUseChanged, this, &MainWindow::updateDatabaseBusyStatus);
+
     ui->actionDropQualifiedCheck->setChecked(Settings::getValue("SchemaDock", "dropQualifiedNames").toBool());
     ui->actionEnquoteNamesCheck->setChecked(Settings::getValue("SchemaDock", "dropEnquotedNames").toBool());
 
@@ -3682,3 +3703,10 @@ void MainWindow::printDbStructure ()
     delete dialog;
     delete document;
 }
+
+void MainWindow::updateDatabaseBusyStatus(bool busy, const QString& user)
+{
+    statusBusyLabel->setText(tr("Busy (%1)").arg(user));
+    statusBusyLabel->setVisible(busy);
+    statusStopButton->setVisible(busy);
+}

src/MainWindow.h

@@ -10,12 +10,7 @@
 #include <QMainWindow>
 #include <QMap>
 
-class QDragEnterEvent;
 class EditDialog;
-class QIntValidator;
-class QLabel;
-class QModelIndex;
-class QPersistentModelIndex;
 class SqliteTableModel;
 class DbStructureModel;
 class RemoteDock;
@@ -23,6 +18,13 @@ class RemoteDatabase;
 class FindReplaceDialog;
 class ExtendedTableWidget;
 
+class QDragEnterEvent;
+class QIntValidator;
+class QModelIndex;
+class QLabel;
+class QPersistentModelIndex;
+class QToolButton;
+
 namespace Ui {
 class MainWindow;
 }
@@ -158,6 +160,8 @@ private:
     QLabel* statusEncodingLabel;
     QLabel* statusEncryptionLabel;
     QLabel* statusReadOnlyLabel;
+    QToolButton* statusStopButton;
+    QLabel* statusBusyLabel;
 
     DbStructureModel* dbStructureModel;
 
@@ -306,6 +310,7 @@ private slots:
     void updateInsertDeleteRecordButton();
     void runSqlNewTab(const QString& query, const QString& title);
     void printDbStructure();
+    void updateDatabaseBusyStatus(bool busy, const QString& user);
 };
 
 #endif

src/icons/icons.qrc

@@ -68,5 +68,6 @@
         <file alias="text_indent">text_indent.png</file>
         <file alias="print">printer.png</file>
         <file alias="project_save">package_save.png</file>
+        <file alias="cancel">cancel.png</file>
     </qresource>
 </RCC>

src/sqlitedb.cpp

@@ -608,6 +608,7 @@ DBBrowserDB::db_pointer_type DBBrowserDB::get(QString user)
 
     db_user = user;
     db_used = true;
+    emit databaseInUseChanged(true, user);
 
     return db_pointer_type(_db, DatabaseReleaser(this));
 }
@@ -1896,3 +1897,11 @@ QString DBBrowserDB::generateTemporaryTableName(const QString& schema) const
             return table_name;
     }
 }
+
+void DBBrowserDB::interruptQuery()
+{
+    if(!_db)
+        return;
+
+    sqlite3_interrupt(_db);
+}

src/sqlitedb.h

@@ -48,6 +48,7 @@ private:
             std::unique_lock<std::mutex> lk(pParent->m);
             pParent->db_used = false;
             lk.unlock();
+            emit pParent->databaseInUseChanged(false, QString());
             pParent->cv.notify_one();
         }
     };
@@ -111,6 +112,11 @@ public:
      */
     bool getRow(const sqlb::ObjectIdentifier& table, const QString& rowid, QVector<QByteArray>& rowdata);
 
+    /**
+     * @brief Interrupts the currenty running statement as soon as possible.
+     */
+    void interruptQuery();
+
 private:
     /**
      * @brief max Queries the table t for the max value of field.
@@ -202,6 +208,7 @@ signals:
     void dbChanged(bool dirty);
     void structureUpdated();
     void requestCollation(QString name, int eTextRep);
+    void databaseInUseChanged(bool busy, QString user);
 
 private:
     /// external code needs to go through get() to obtain access to the database