Merge pull request #4849 from fthoma/table-tcwidth

Use character display width for table padding

internal/ui/format.go

@@ -8,6 +8,8 @@ import (
 	"math/bits"
 	"strconv"
 	"time"
+
+	"golang.org/x/text/width"
 )
 
 func FormatBytes(c uint64) string {
@@ -105,3 +107,24 @@ func ToJSONString(status interface{}) string {
 	}
 	return buf.String()
 }
+
+// TerminalDisplayWidth returns the number of terminal cells needed to display s
+func TerminalDisplayWidth(s string) int {
+	width := 0
+	for _, r := range s {
+		width += terminalDisplayRuneWidth(r)
+	}
+
+	return width
+}
+
+func terminalDisplayRuneWidth(r rune) int {
+	switch width.LookupRune(r).Kind() {
+	case width.EastAsianWide, width.EastAsianFullwidth:
+		return 2
+	case width.EastAsianNarrow, width.EastAsianHalfwidth, width.EastAsianAmbiguous, width.Neutral:
+		return 1
+	default:
+		return 0
+	}
+}

internal/ui/format_test.go

@@ -84,3 +84,21 @@ func TestParseBytesInvalid(t *testing.T) {
 		test.Equals(t, int64(0), v)
 	}
 }
+
+func TestTerminalDisplayWidth(t *testing.T) {
+	for _, c := range []struct {
+		input string
+		want  int
+	}{
+		{"foo", 3},
+		{"aéb", 3},
+		{"ab", 3},
+		{"a’b", 3},
+		{"aあb", 4},
+	} {
+		if got := TerminalDisplayWidth(c.input); got != c.want {
+			t.Errorf("wrong display width for '%s', want %d, got %d", c.input, c.want, got)
+		}
+	}
+
+}

internal/ui/table/table.go

@@ -6,6 +6,8 @@ import (
 	"strings"
 
 	"text/template"
+
+	"github.com/restic/restic/internal/ui"
 )
 
 // Table contains data for a table to be printed.
@@ -89,7 +91,7 @@ func printLine(w io.Writer, print func(io.Writer, string) error, sep string, dat
 			}
 
 			// apply padding
-			pad := widths[fieldNum] - len(v)
+			pad := widths[fieldNum] - ui.TerminalDisplayWidth(v)
 			if pad > 0 {
 				v += strings.Repeat(" ", pad)
 			}
@@ -139,16 +141,18 @@ func (t *Table) Write(w io.Writer) error {
 	columnWidths := make([]int, columns)
 	for i, desc := range t.columns {
 		for _, line := range strings.Split(desc, "\n") {
-			if columnWidths[i] < len(line) {
-				columnWidths[i] = len(desc)
+			width := ui.TerminalDisplayWidth(line)
+			if columnWidths[i] < width {
+				columnWidths[i] = width
 			}
 		}
 	}
 	for _, line := range lines {
 		for i, content := range line {
 			for _, l := range strings.Split(content, "\n") {
-				if columnWidths[i] < len(l) {
-					columnWidths[i] = len(l)
+				width := ui.TerminalDisplayWidth(l)
+				if columnWidths[i] < width {
+					columnWidths[i] = width
 				}
 			}
 		}
@@ -159,7 +163,7 @@ func (t *Table) Write(w io.Writer) error {
 	for _, width := range columnWidths {
 		totalWidth += width
 	}
-	totalWidth += (columns - 1) * len(t.CellSeparator)
+	totalWidth += (columns - 1) * ui.TerminalDisplayWidth(t.CellSeparator)
 
 	// write header
 	if len(t.columns) > 0 {

internal/ui/table/table_test.go

@@ -29,6 +29,21 @@ first column
 ----------------------
 data: first data field
 ----------------------
+`,
+		},
+		{
+			func(t testing.TB) *Table {
+				table := New()
+				table.AddColumn("first\ncolumn", "{{.First}}")
+				table.AddRow(struct{ First string }{"data"})
+				return table
+			},
+			`
+first
+column
+------
+data
+------
 `,
 		},
 		{
@@ -126,7 +141,7 @@ foo        2018-08-19 22:22:22  xxx  other  /home/user/other
 					Time       string
 					Tags, Dirs []string
 				}
-				table.AddRow(data{"foo", "2018-08-19 22:22:22", []string{"work", "go"}, []string{"/home/user/work", "/home/user/go"}})
+				table.AddRow(data{"foo", "2018-08-19 22:22:22", []string{"work", "go’s"}, []string{"/home/user/work", "/home/user/go"}})
 				table.AddRow(data{"foo", "2018-08-19 22:22:22", []string{"other"}, []string{"/home/user/other"}})
 				table.AddRow(data{"foo", "2018-08-19 22:22:22", []string{"other", "bar"}, []string{"/home/user/other"}})
 				return table
@@ -135,7 +150,7 @@ foo        2018-08-19 22:22:22  xxx  other  /home/user/other
 host name  time                 zz   tags   dirs
 ------------------------------------------------------------
 foo        2018-08-19 22:22:22  xxx  work   /home/user/work
-                                     go     /home/user/go
+                                     go’s   /home/user/go
 foo        2018-08-19 22:22:22  xxx  other  /home/user/other
 foo        2018-08-19 22:22:22  xxx  other  /home/user/other
                                      bar