Add Java Epoch format conversion

Grif392 · MKleusberg · commit 46ec0197193a · 2017-09-11T00:30:23.000+02:00
Java epoch is measured in milliseconds from unix 0; conversion is a
(roundabout, best I could find) way to convert milliseconds into a
SQLite datetime while keeping millisecond resolution.

Easier alternative would be column_name / 1000, but loses _some_
theoretical resolution.
diff --git a/src/ColumnDisplayFormatDialog.cpp b/src/ColumnDisplayFormatDialog.cpp
@@ -20,6 +20,7 @@ ColumnDisplayFormatDialog::ColumnDisplayFormatDialog(const QString& colname, QSt
     ui->comboDisplayFormat->addItem(tr("Octal number"), "octal");
     ui->comboDisplayFormat->addItem(tr("Round number"), "round");
     ui->comboDisplayFormat->addItem(tr("Unix epoch to date"), "epoch");
+    ui->comboDisplayFormat->addItem(tr("Java epoch (milliseconds) to date"), "javaEpoch");
     ui->comboDisplayFormat->addItem(tr("Upper case"), "upper");
     ui->comboDisplayFormat->addItem(tr("Windows DATE to date"), "winDate");
     ui->labelDisplayFormat->setText(ui->labelDisplayFormat->text().arg(column_name));
@@ -61,6 +62,8 @@ void ColumnDisplayFormatDialog::updateSqlCode()
         ui->editDisplayFormat->setText("upper(" + sqlb::escapeIdentifier(column_name) + ")");
     else if(format == "epoch")
         ui->editDisplayFormat->setText("datetime(" + sqlb::escapeIdentifier(column_name) + ", 'unixepoch')");
+    else if(format == "javaEpoch")
+        ui->editDisplayFormat->setText("strftime('%Y-%m-%d %H:%M:%S.', " + sqlb::escapeIdentifier(column_name) + "/1000, 'unixepoch') || (" + sqlb::escapeIdentifier(column_name) + "%1000)");
     else if(format == "winDate")
         ui->editDisplayFormat->setText("datetime ('1899-12-30', " + sqlb::escapeIdentifier(column_name) + " || \" days\" )");
     else if(format == "appleDate")
