sqlite: refactor separate populateRows, populateColumns

sqlite.go

@@ -77,36 +77,16 @@ func (ld *sqliteLoadedDatabase) RenderForNav(f *TMainForm, ndata *navData) {
 		// Use SELECT form instead of common PRAGMA table_info so we can just get names
 		// We could possibly get this from the main data select, but this will
 		// work even when there are 0 results
-		colr, err := ld.db.Query(`SELECT name FROM pragma_table_info(?)`, tableName)
+		columnNames, err := ld.sqliteGetColumnNamesForTable(tableName)
 		if err != nil {
 			vcl.ShowMessageFmt("Failed to load columns for table %q: %s", tableName, err.Error())
 			return
 		}
-		defer colr.Close()
 
-		f.contentBox.Columns().Clear()
+		populateColumns(columnNames, f.contentBox)
-		numColumns := 0
-		for colr.Next() {
 
-			var columnName string
+		// Select count(*) so we know to display a warning if there are too many entries
-			err = colr.Scan(&columnName)
+		// TODO
-			if err != nil {
-				vcl.ShowMessageFmt("Failed to read column names for table %q: %s", tableName, err.Error())
-				return
-			}
-
-			col := f.contentBox.Columns().Add()
-			col.SetCaption(columnName)
-			col.SetWidth(MY_WIDTH)
-			col.SetAlignment(types.TaLeftJustify)
-
-			numColumns++
-		}
-		if colr.Err() != nil {
-			vcl.ShowMessageFmt("Failed to load columns for table %q: %s", tableName, err.Error())
-			return
-		}
-		colr.Close() // will be double-closed
 
 		// Select * with small limit
 		datar, err := ld.db.Query(`SELECT * FROM ` + tableName + ` LIMIT 1000`) // WARNING can't prepare this parameter, but it comes from the DB (trusted)
@@ -115,27 +95,7 @@ func (ld *sqliteLoadedDatabase) RenderForNav(f *TMainForm, ndata *navData) {
 			return
 		}
 		defer datar.Close()
-
+		populateRows(datar, f.contentBox)
-		for datar.Next() {
-			fields := make([]interface{}, numColumns)
-			pfields := make([]interface{}, numColumns)
-			for i := 0; i < numColumns; i += 1 {
-				pfields[i] = &fields[i]
-			}
-
-			err = datar.Scan(pfields...)
-			if err != nil {
-				vcl.ShowMessageFmt("Failed to load data for table %q: %s", tableName, err.Error())
-				return
-			}
-
-			dataEntry := f.contentBox.Items().Add()
-			dataEntry.SetCaption(formatAny(fields[0]))
-			for i := 1; i < len(fields); i += 1 {
-				dataEntry.SubItems().Add(formatAny(fields[i]))
-			}
-
-		}
 
 		// We successfully populated the data grid
 		f.contentBox.SetEnabled(true)
@@ -147,6 +107,74 @@ func (ld *sqliteLoadedDatabase) RenderForNav(f *TMainForm, ndata *navData) {
 
 }
 
+func (ld *sqliteLoadedDatabase) sqliteGetColumnNamesForTable(tableName string) ([]string, error) {
+	colr, err := ld.db.Query(`SELECT name FROM pragma_table_info(?)`, tableName)
+	if err != nil {
+		return nil, fmt.Errorf("Query: %w", err)
+	}
+	defer colr.Close()
+
+	var ret []string
+
+	for colr.Next() {
+
+		var columnName string
+		err = colr.Scan(&columnName)
+		if err != nil {
+			return nil, fmt.Errorf("Scan: %w", colr.Err())
+		}
+
+		ret = append(ret, columnName)
+	}
+	if colr.Err() != nil {
+		return nil, colr.Err()
+	}
+
+	return ret, nil
+}
+
+func populateColumns(names []string, dest *vcl.TListView) {
+	dest.Columns().Clear()
+	for _, columnName := range names {
+		col := dest.Columns().Add()
+		col.SetCaption(columnName)
+		col.SetWidth(MY_WIDTH)
+		col.SetAlignment(types.TaLeftJustify)
+	}
+}
+
+func populateRows(rr *sql.Rows, dest *vcl.TListView) {
+
+	numColumns := int(dest.Columns().Count())
+
+	for rr.Next() {
+		fields := make([]interface{}, numColumns)
+		pfields := make([]interface{}, numColumns)
+		for i := 0; i < numColumns; i += 1 {
+			pfields[i] = &fields[i]
+		}
+
+		err := rr.Scan(pfields...)
+		if err != nil {
+			vcl.ShowMessageFmt("Failed to load data: %s", err.Error())
+			return
+		}
+
+		dataEntry := dest.Items().Add()
+		dataEntry.SetCaption(formatAny(fields[0]))
+		for i := 1; i < len(fields); i += 1 {
+			dataEntry.SubItems().Add(formatAny(fields[i]))
+		}
+
+	}
+	if rr.Err() != nil {
+		vcl.ShowMessageFmt("Failed to load data: %s", rr.Err().Error())
+		return
+	}
+}
+
+}
+
 func (ld *sqliteLoadedDatabase) NavChildren(ndata *navData) ([]string, error) {
 
 	if len(ndata.bucketPath) == 0 {