Method printCellValue

cf/terminal/table.go:259–300

printCellValue pads the specified string to the width of the given column, adds the spacing between columns, and returns the result.

(result io.Writer, transformer rowTransformer, col, last int, value string)

// printCellValue pads the specified string to the width of the given
// column, adds the spacing between columns, and returns the result.
func (t *Table) printCellValue(result io.Writer, transformer rowTransformer, col, last int, value string) error {
	value = trim(transformer.Transform(col, trim(value)))
	fmt.Fprint(result, value)

	// Pad all columns, but the last in this row (with the size of
	// the header row limiting this). This ensures that most of
	// the irrelevant spacing is not printed. At the moment
	// irrelevant spacing can only occur when printing a row with
	// multi-line cells, introducing a physical short line for a
	// long logical row. Getting rid of that requires fixing in
	// printRow.
	//
	//  Note how the inter-column spacing is also irrelevant for
	//  that last column.

	if col < last {
		// (**) See also 'calculateMaxSize' (cMS). Here and
		// there we have to apply identical transformations to
		// the cell value to get matching cell width
		// information. If they do not match then we may here
		// compute a cell width larger than the max width
		// found by cMS, derive a negative padding length from
		// that, and subsequently return an error. What was
		// further missing is trimming before entering the
		// user-transform. Especially with color transforms
		// any trailing space going in will not be removable
		// for print.
		//
		// This happened for
		// https://www.pivotaltracker.com/n/projects/892938/stories/117404629

		decolorizedLength, err := visibleSize(trim(Decolorize(value)))
		if err != nil {
			return err
		}
		padlen := t.columnWidth[col] - decolorizedLength
		padding := strings.Repeat(" ", padlen)
		fmt.Fprint(result, padding)
		fmt.Fprint(result, t.colSpacing)
	}
	return nil
}

// rowTransformer is an interface behind which we can specify how to
// transform the strings of an entire row on a column-by-column basis.