Simplify code

Merge two very similar functions into one while keeping the best parts
of both.

src/sqlitedb.cpp

@@ -986,16 +986,18 @@ bool DBBrowserDB::executeMultiSQL(const QString& statement, bool dirty, bool log
     return true;
 }
 
-QVariant DBBrowserDB::querySingleValueFromDb(const QString& statement, bool log)
+QByteArray DBBrowserDB::querySingleValueFromDb(const QString& sql, bool log)
 {
     waitForDbRelease();
     if(!_db)
-        return QVariant();
+        return QByteArray();
 
     if(log)
-        logSQL(statement, kLogMsg_App);
+        logSQL(sql, kLogMsg_App);
 
-    QByteArray utf8Query = statement.toUtf8();
+    QByteArray retval;
+
+    QByteArray utf8Query = sql.toUtf8();
     sqlite3_stmt* stmt;
     if(sqlite3_prepare_v2(_db, utf8Query, utf8Query.size(), &stmt, nullptr) == SQLITE_OK)
     {
@@ -1005,16 +1007,22 @@ QVariant DBBrowserDB::querySingleValueFromDb(const QString& statement, bool log)
             {
                 int bytes = sqlite3_column_bytes(stmt, 0);
                 if(bytes)
-                    return QByteArray(static_cast<const char*>(sqlite3_column_blob(stmt, 0)), bytes);
+                    retval = QByteArray(static_cast<const char*>(sqlite3_column_blob(stmt, 0)), bytes);
                 else
-                    return "";
+                    retval = "";
             }
 
             sqlite3_finalize(stmt);
+        } else {
+            lastErrorMessage = tr("didn't receive any output from %1").arg(sql);
+            qWarning() << lastErrorMessage;
         }
+    } else {
+        lastErrorMessage = tr("could not execute command: %1").arg(sqlite3_errmsg(_db));
+        qWarning() << lastErrorMessage;
     }
 
-    return QVariant();
+    return retval;
 }
 
 bool DBBrowserDB::getRow(const sqlb::ObjectIdentifier& table, const QString& rowid, QVector<QByteArray>& rowdata)
@@ -1725,36 +1733,6 @@ void DBBrowserDB::updateSchema()
     emit structureUpdated();
 }
 
-QString DBBrowserDB::selectSingleCell(const QString& sql, bool logsql)
-{
-    waitForDbRelease();
-
-    if(!isOpen())
-        return QString();
-
-    sqlite3_stmt* vm;
-    const char* tail;
-    QString retval;
-
-    // Get value from DB
-    int err = sqlite3_prepare_v2(_db, sql.toUtf8(), sql.toUtf8().length(), &vm, &tail);
-    if(err == SQLITE_OK){
-        if (logsql)
-            logSQL(sql, kLogMsg_App);
-        if(sqlite3_step(vm) == SQLITE_ROW)
-            retval = QString::fromUtf8((const char *) sqlite3_column_text(vm, 0));
-        else
-            qWarning() << tr("didn't receive any output from %1").arg(sql);
-
-        sqlite3_finalize(vm);
-    } else {
-        qWarning() << tr("could not execute command: %1, %2").arg(err).arg(sqlite3_errmsg(_db));
-    }
-
-    // Return it
-    return retval;
-}
-
 QString DBBrowserDB::getPragma(const QString& pragma)
 {
     QString sql;
@@ -1762,7 +1740,7 @@ QString DBBrowserDB::getPragma(const QString& pragma)
         sql = "SELECT 'x' NOT LIKE 'X'";
     else
         sql = QString("PRAGMA %1").arg(pragma);
-    return selectSingleCell(sql);
+    return querySingleValueFromDb(sql);
 }
 
 bool DBBrowserDB::setPragma(const QString& pragma, const QString& value)

src/sqlitedb.h

@@ -96,7 +96,7 @@ public:
 
     bool executeSQL(QString statement, bool dirtyDB = true, bool logsql = true);
     bool executeMultiSQL(const QString& statement, bool dirty = true, bool log = false);
-    QVariant querySingleValueFromDb(const QString& statement, bool log = true);
+    QByteArray querySingleValueFromDb(const QString& sql, bool log = true);
 
     const QString& lastError() const { return lastErrorMessage; }
 
@@ -176,7 +176,6 @@ public:
     /// log an SQL statement [thread-safe]
     void logSQL(QString statement, int msgtype);
 
-    QString selectSingleCell(const QString& sql, bool logsql = true);
     QString getPragma(const QString& pragma);
     bool setPragma(const QString& pragma, const QString& value);
     bool setPragma(const QString& pragma, const QString& value, QString& originalvalue);

src/sqlitetablemodel.cpp

@@ -314,7 +314,7 @@ QVariant SqliteTableModel::data(const QModelIndex &index, int role) const
                 else
                     sql = QString("SELECT '%1' %2").arg(value, eachCondFormat.sqlCondition());
 
-                if (m_db.selectSingleCell(sql, false) == "1")
+                if (m_db.querySingleValueFromDb(sql, false) == "1")
                     return eachCondFormat.color();
             }
         }